Glossary of botanical terms
Many of the terms used in Wikipedia glossaries (often most) are already defined and explained within Wikipedia itself. However, lists like the following indicate where new articles need to be written and are also useful for looking up and comparing large numbers of terms together.
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abaxial: the side away from the axis, for instance the lower surface of a leaf.
  • abort: to abandon development of a structure of organ.

  • abscission
    Abscission is a term used in several areas of biology. In plant sciences it most commonly refers to the process by which a plant drops one or more of its parts, such as a leaf, fruit, flower or seed...

    : (adjective abscissile): a plant's normal shedding of an organ that is mature or aged, e.g. a ripe fruit or an old leaf.

  • accrescent: increasing in size with age, such as a calyx that continues to grow after the corolla has fallen, for example in Physalis peruviana
    Physalis peruviana
    Physalis peruviana is the plant and its fruit, also known as cape gooseberry , Inca berry, Aztec berry, golden berry, giant ground cherry, Peruvian groundcherry, Peruvian cherry , poha , ras bhari , aguaymanto , uvilla ,...


  • -aceae: the suffix added to the stem of a generic name to form the name of a family.

  • achene
    An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate and indehiscent...

    : a dry 1-seeded indehiscent fruit; e.g. members of the Ranunculaceae.

  • acicular: slender or needle-shaped. See Leaf shape
    Leaf shape
    In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...


  • acropetal: moving from roots to leaves, e.g. of molecular signals in plants.

actinomorphic: regular; radially symmetrical; may be bisected into similar halves in at least two planes. Generally applies to flowers in which the perianth segments within each whorl are alike in size and shape; compare irregular, regular, zygomorphic.
  • aculeate: armed with prickles; e.g. the stem of a rose.

  • acuminate: tapering gradually to a point.

acute: sharply pointed; converging edges making an angle of less than 90°; compare obtuse.
adaxial: the side next to the axis; e.g. the upper surface of a leaf.
  • adnate
    Adnation in plants is the "union of unlike parts; organically united or fused with another dissimilar part, e.g. an ovary to a calyx tube, or stamens to petals". This is in contrast to connation, the fusion of similar organs....

    : fused to an organ of a different kind; e.g. a stamen fused to a petal; cf. connate.

  • adventitious
    Adventitious has various meanings in various disciplines and in general usage.Adventitious is from the Latin root advenire, meaning "to come or be superadded" and in correct English the meanings tend to have connections to accidental or casual occurrence...

    : a structure produced in an abnormal position; e.g. an adventitious bud produced from a stem rather than from the axil of a leaf.

  • adventive: introduced accidentally (usually referring to weeds).

aerial: of the air; growing or borne above the surface of the ground.
  • aestivation: the arrangement of sepals and petals or their lobes in an unexpanded flower bud; cf. vernation arrangement of leaves in a bud.

  • affinis
    Species affinis
    A Species affinis is a species related to but not identical with the named species....

    : with affinity to others, akin to; often used for a provisionally recognized but unnamed taxon considered close to that name, perhaps a hybrid or extreme variant.

  • aggregate fruit: a cluster of fruits formed from the free carpels of one flower, e.g. blackberry; cf. multiple fruit.

  • agricultural weed: see weed.

  • -ales: suffix to the stem of a generic name or descriptive name to indicate that it applies to a taxon of the rank of order.

  • alien: differing in nature, foreign; a plant introduced from elsewhere (exotic, introduced, non-native, non-indigenous).

  • alkaloid
    Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...

    : molecule with a nitrogenous base, many used as drugs; e.g. morphine, quinine, strychnine.

alternate: (as adjective) leaves or flowers borne singly at different levels along a stem includes spiralled parts; or (as verb) when something occurs between something else, for example stamens alternating with petals; compare opposite.
  • amphitropous: when the ovule is bent so that both ends are near each other; cf. anatropous, campylotropous, orthotropous.

  • amplexicaul: with the base dilated and clasping the stem, usually of leaves.

  • anastomosing: when veins are joined by cross-veins to form a network.

  • anatropous: when an ovule is inverted so that the micropyle faces the placenta (this is the most common ovule orientation in flowering plants); cf. amphitropous, campylotropous, orthotropous.

  • androdioecious: of plants, having bisexual flowers and male flowers on separate individuals; cf. andromonoecious, polygamodioecious, polygamomonoecious, polygamous.

  • androecium: male parts of flower; the stamens of a flower collectively; cf. gynoecium.

  • androgynophore: a stalk bearing both the androecium and gynoecium of a flower above the level of insertion of the perianth.

  • androgynous: with male and female flowers in the same inflorescence.

  • andromonoecious: of plants, having bisexual and male flowers on the same individual; cf. andromonoecious, polygamodioecious, polygamomonoecious, polygamous.

  • Anemophily
    Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Anemophilous plants may be either gymnosperms or angiosperms ....

    : pollination by wind.

  • angiosperms: 'flowering plants'; plants with developing seeds enclosed in an ovary.

  • annual
    Annual plant
    An annual plant is a plant that usually germinates, flowers, and dies in a year or season. True annuals will only live longer than a year if they are prevented from setting seed...

    : a plant that completes its life cycle and dies within one year.

anterior: away from the axis; usually abaxial.
anther: pollen-bearing part of the stamen.
  • anthesis
    Anthesis is the period during which a flower is fully open and functional. It may also refer to the onset of that period.The onset of anthesis is spectacular in some species. In Banksia species, for example, anthesis involves the extension of the style far beyond the upper perianth parts...

    : time of flowering; the stage at which the pollen is released from the anthers inside the bud onto the pollen presenter, usually corresponding with flower opening.

  • antrorse: directed towards or upwards, e.g. of hairs on a stem; cf. retrorse.

  • apetalous: without petals.

  • apex (apical): the tip; the point furthest from the point of attachment; plural apices.

  • apiculate: terminating in a short sharp flexible point; less abrupt than mucronate.

  • apocarpous: of a gynoecium consisting with one or more carpels which are free from one another (or almost so); e.g. Ranunculaceae, Dilleniaceae.

  • apomixis
    In botany, apomixis was defined by Winkler as replacement of the normal sexual reproduction by asexual reproduction, without fertilization. This definition notably does not mention meiosis...

    : reproduction, where viable seed or spores are produced without fertilization. A plant produced in this way is an apomict.

  • appendage
    In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body . It is a general term that covers any of the homologous body parts that may extend from a body segment...

    : a secondary part attached to the main structure; an external growth that seldom has any obvious function.

  • appressed: pressed closely, but not fused; e.g. leaves against a stem.

Aquatic plant
Aquatic plants are plants that have adapted to living in aquatic environments. They are also referred to as hydrophytes or aquatic macrophytes. These plants require special adaptations for living submerged in water, or at the water's surface. Aquatic plants can only grow in water or in soil that is...

: plants whose natural habitat is water: living in or on water for all or a substantial part of the organism's life span, generally restricted to fresh or inland waters.
  • arborescent
    Arborescent is a term used by the French thinkers Deleuze and Guattari to characterize thinking marked by insistence on totalizing principles, binarism and dualism...

    : tree-like in growth or general appearance.

  • arboretum
    An arboretum in a narrow sense is a collection of trees only. Related collections include a fruticetum , and a viticetum, a collection of vines. More commonly, today, an arboretum is a botanical garden containing living collections of woody plants intended at least partly for scientific study...

    : (plural arboreta) a taxonomically arranged collection of trees.

  • archaeophyte
    An archaeophyte is a plant species which is non-native to a geographical region, but which was an introduced species in "ancient" times, rather than being a modern introduction. Those arriving after are called neophytes...

    : an non-native plant that has been present in a geographic area for some time; cf. neophyte.

  • areole
    Areoles are an important diagnostic feature of cacti, and identify them as a family distinct from other succulent plants. The areoles on cacti are clearly visible; they generally appear as small light- to dark-colored bumps, out of which grow clusters of spines...

    : (from areola) a space between the threads of a net; e.g. that part of a leaf surface defined by each of the elements of a vein network; as with cacti, the area between the veinlets of a leaf or the region of a cactus bearing the flowers and/or spines.

  • aril
    An aril is any specialized outgrowth from the funiculus that covers or is attached to the seed. It is sometimes applied to any appendage or thickening of the seed coat in flowering plants, such as the edible parts of the mangosteen and pomegranate fruit, the mace of the nutmeg seed, or the...

    (adjective arillate): a membranous or fleshy appendage (formed by expansion of the funicle) which partly or wholly covers a seed; e.g. the fleshy outer layer of lychee fruit and as found in Sapindaceae.

  • aristate: with a stiff, bristle-like awn or tip.

  • article: a segment of a jointed stem or of a fruit with constrictions between the seeds; an organ part that separates easily from the rest of the organ at a joint or articulation.

articulate: jointed; separating freely, leaving a clean scar; for example the fronds of certain ferns where they join the rhizome.
  • ascending: spreading horizontally, then becoming erect.

  • asexual
    Asexual reproduction
    Asexual reproduction is a mode of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only, it is reproduction which does not involve meiosis, ploidy reduction, or fertilization. A more stringent definition is agamogenesis which is reproduction without...

    : of reproduction that does not involve the gametes; i.e. vegetative reproduction.

  • attenuate: narrowing gradually.

  • auricle
    Auricle (botany)
    In botany, an auricle is a small ear-like projection from the base of a leaf or petal....

    (adjective auriculate): ear-shaped lobe.

awn: fine bristle-like appendage; e.g. terminating or on the back of glumes and/or lemmas of some grass spikelets.
axil: the upper angle between one part of a plant and another; e.g. the stem and a leaf.
  • axile: on an axis; of a placenta, on the central axis of the ovary.

  • axillary: borne in or arising from the axil of a leaf.

axis: a line passing through the centre of something; it usually refers to the main stem of a whole plant or inflorescence.


  • bark
    Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...

    : the protective external layer of tissue on the stems and roots of trees and shrubs; includes all of the living and non-living tissue external to the cambium.

basal: at the base, situated or attached at the base.
  • basifixed: something attached by its base; e.g. an anther attached to the filament.

  • basipetal: developing sequentially from the apex towards the base (i.e. with the youngest towards the base); e.g. of flowers in an inflorescence. Also, moving from leaves to roots, e.g. of molecular signals in plants.

  • beak: a pointed projection.

The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....

: an indehiscent fruit, with the seeds immersed in the pulp, for instance tomato
The word "tomato" may refer to the plant or the edible, typically red, fruit which it bears. Originating in South America, the tomato was spread around the world following the Spanish colonization of the Americas, and its many varieties are now widely grown, often in greenhouses in cooler...

  • biennial
    Biennial plant
    A biennial plant is a flowering plant that takes two years to complete its biological lifecycle. In the first year the plant grows leaves, stems, and roots , then it enters a period of dormancy over the colder months. Usually the stem remains very short and the leaves are low to the ground, forming...

    : plant which completes its life cycle and dies within the second year; usually also forms a basal rosette of leaves the first year and flowers and fruits the second year.

  • bifid: forked; cut in two for about half its length.

  • bilabiate: having two lips; e.g. the form of the petals in many irregular flowers.

  • bilateral: arranged on opposite sides; e.g. leaves on a stem.

  • binomial
    Binomial nomenclature
    Binomial nomenclature is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages...

    : making use of names consisting of two words to form the scientific name (or combination) in a Latin form. For example, where the first is the name of the genus to which the species belongs, and the second is the epithet given to that species to distinguish it from others in the same genus.

  • binomial nomenclature
    Binomial nomenclature
    Binomial nomenclature is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages...

    : the system of nomenclature in which the scientific name of a species (and not of a taxon at any other rank) is a combination of two names, the first name being the generic name. The second name is referred to botanically as the specific epithet. Note that the two names constitute the species name, not just the second word.

  • bipinnate: twice pinnate; for example of a compound leaf with individual leaflets pinnately divided.

  • bipinnatisect: a pinnatisect leaf with deeply dissected segments.

bisexual: bearing both male and female reproductive organs; usually, flowers with both stamens and carpels; hermaphrodite. See Sexual reproduction in plants.
  • bitegmic: (of an ovule), covered by two integuments.

  • bole: the trunk of a tree, usually below the lowest branch; cf. canopy.

  • blade: the lamina or flattened part of a leaf, excluding the stalk.

  • bloom
    Epicuticular wax
    In botany, the plant cuticle is covered by epicuticular wax or bloom mainly consistingof straight-chain aliphatic hydrocarbons with a variety of substituted groups, serving to decrease moisture loss and decay...

    : a fine white or bluish waxy powder occurring on plant parts, usually stems, leaves and fruits. It is easily removed by rubbing.

  • bract
    In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale. Bracts are often different from foliage leaves. They may be smaller, larger, or of a different color, shape, or texture...

    : modified leaf associated with flower or inflorescence, differing in shape, size or colour from other leaves (and without an axillary bud).

  • bracteole: small bracts borne singly or in pairs on the pedicel or calyx.

  • branchlet: a small branch.

  • bristle
    A bristle is a stiff hair or feather. Also used are synthetic materials such as nylon in items such as brooms and sweepers. Bristles are often used to make brushes for cleaning uses, as they are strongly abrasive; common examples include the toothbrush and toilet brush...

    (adjective: bristly): straight stiff hair (smooth or with minute teeth) or upper part of an awn (when the latter is bent and has a lower, stouter, and usually twisted part, called the column).

  • bryophyte
    Bryophyte is a traditional name used to refer to all embryophytes that do not have true vascular tissue and are therefore called 'non-vascular plants'. Some bryophytes do have specialized tissues for the transport of water; however since these do not contain lignin, they are not considered to be...

    : a botanical group including mosses and liverworts. Technically a classification of plants including three classes: hornworts (Anthocerotae), liverworts (Hepaticae) and mosses (Musci).

A bulb is a short stem with fleshy leaves or leaf bases. The leaves often function as food storage organs during dormancy.A bulb's leaf bases, known as scales, generally do not support leaves, but contain food reserves to enable the plant to survive adverse conditions. At the center of the bulb is...

: thick storage organ, usually underground, consisting of a stem and leaf bases (the inner ones fleshy).
  • bulbel: a bulb arising from another bulb.

  • bulbil: small deciduous bulb or tuber formed in the axil of a leaf or pinna; a means of vegetative propagation.

  • bulblet: a bulb arising from another bulb; a bulbil.

bullate: blistered or puckered.
  • bur
    BUR may refer to:* Bur, a saying by Gucci Mane* Burs , a Germanic tribe* Bob Hope Airport, Burbank, California * Burmese language * Burkina Faso...

    : loosely, a prickly fruit; a rough or prickly propagule consisting of a seed or fruit and associated floral parts or bracts.

  • buttress root
    Buttress root
    Buttress are large roots on all sides of a big bottomed tree or shallowly rooted tree. Typically, they are found in nutrient-poor rainforest soils and do not penetrate to deeper layers. They prevent the tree from falling over while also gathering more nutrients...

    : a root growing from the above-ground stem or trunk, and providing support, as in the case of Ficus macrophylla, the Moreton Bay Fig.


caducous: falling off early; compare persistent.
  • caespitose: tufted; e.g. the growth form of some grasses.

  • callus
    A callus is an especially toughened area of skin which has become relatively thick and hard in response to repeated friction, pressure, or other irritation. Rubbing that is too frequent or forceful will cause blisters rather than allow calluses to form. Since repeated contact is required, calluses...

    (plural calli): generally, a protruding mass of tissue; in orchids, fleshy outgrowths from the labellum which can be variously shaped from papillae to plates; in grasses, hardened extension from the base of a floret (formed from the rachilla joint and/or the base of the lemma) which may or may not elongate and is often covered in hairs or bristles.

  • calycophyll: a leaf-like structure formed from a sepal or calyx lobe which enlarges, usually many-fold, before or after anthesis, especially when most of the sepals or calyx lobes retain their original size. More extreme than an accrescent calyx, calycophylls are found in Rubiaceae. cf. semaphyll, pterophyll.

  • calyculus: a false calyx, a type of epicalyx that is small and rudimentary in appearance.

  • calyptra
    Calyptra is a scientific term used in botany. It describes a feature in plant morphology.-Bryophytes:In bryophytes, the calyptra is an enlarged archegonial venter that protects the capsule containing the embryonic sporophyte . The calyptra is usually lost before the spores are released from the...

    : a hood or lid; see operculum.

  • calyx
    A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...

    (plural calyces): the outer whorl of a flower, usually green; the sepals of one flower collectively.

  • calyx tube: a tube formed by the fusion of the sepals (calyx), at least at the base.

  • campanulate: bell-shaped.

  • campylotropous: when the ovule is oriented transversely (i.e. with its axis at right angles to its stalk) and with a curved embyro sac; cf. amphitropous, anatropous, orthotropous.

  • canaliculate: channelled; with a longitudinal groove.

canopy: the branches and foliage of a tree; crown; cf. trunk.
  • capillary
    Capillaries are the smallest of a body's blood vessels and are parts of the microcirculation. They are only 1 cell thick. These microvessels, measuring 5-10 μm in diameter, connect arterioles and venules, and enable the exchange of water, oxygen, carbon dioxide, and many other nutrient and waste...

    : (noun) a tube, pore or passage with a narrow internal cross-section; (adjective) slender, hair-like.

  • capitate: with knob-like head; of an inflorescence, with the flowers unstalked and aggregated into a dense cluster; of a stigma, like the head of a pin.

capitulum: a dense cluster of sessile, or almost sessile, flowers or florets; a head.
  • capsule
    Capsule (fruit)
    In botany a capsule is a type of simple, dry fruit produced by many species of flowering plants. A capsule is a structure composed of two or more carpels that in most cases is dehiscent, i.e. at maturity, it splits apart to release the seeds within. A few capsules are indehiscent, for example...

    : a dry fruit formed from two of more united carpels and dehiscing when ripe (usually by splitting into pieces or opening at summit by teeth or pores).

  • carina (adjective carinate): keel.

carpel: a female organ borne at the centre of a flower, consisting of an ovary, a style and a stigma. The gynoecium is the collective term for all the carpels of a single flower.
  • cartilaginous: hard and tough; gristly.

  • caryopsis
    In botany, a caryopsis is a type of simple dry fruit — one that is monocarpelate and indehiscent and resembles an achene, except that in a caryopsis the pericarp is fused with the thin seed coat....

    : a dry, indehiscent, one-seeded fruit in which the seed coat is closely fused to the fruit wall, as in most grasses.

  • casual alien: a plant that appears with no apparent human assistance but does not develop a sustained population(s). Plants that persist only by new introductions; cf. alien.

  • cataphyll
    In plant morphology, a cataphyll is a leaf whose primary function is something other than photosynthesis...

    : Early leaf forms of plants or shoots, such as cotyledons, bud-scales, rhizome-scales; anatomically they are leaves, but do not develop to perform the usual functions of photosynthetic leaves.

  • catkin
    A catkin or ament is a slim, cylindrical flower cluster, with inconspicuous or no petals, usually wind-pollinated but sometimes insect pollinated . They contain many, usually unisexual flowers, arranged closely along a central stem which is often drooping...

    : a spike, usually pendulous, in which the mostly small flowers are unisexual and without a conspicuous perianth; e.g. willows, poplars, oaks and casuarinas. The individual flowers often have scaly bracts; they are generally wind-pollinated. The catkins are usually shed as a unit.

  • caudate: having a narrow tail-like appendage.

  • cauline: borne on an aerial stem, e.g. leaves, flower or fruits (when applied to the latter two organs, usually referring to older stems; = cauliflorous).

  • cell
    Cell (biology)
    The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....

    : (1) basic (microscopic) unit of plant structure, generally consisting of compartments in a viscous fluid surrounded by a wall; (2) cavity of an anther or ovary.

  • centrifixed: of a two-branched organ attached by its centre, e.g. a hair, or anther.

  • chartaceous: with a papery texture.

  • chamber: cavity of an ovary.

  • chasmogamous: of flowers that are pollinated when the perianth is open; cf. cleistogamous.

  • chimera
    Chimera (plant)
    Chimeras in botany are usually single organisms composed of two genetically different types of tissue. They occur in plants, on the same general basis as with animal chimeras...

    : an individual composed of two or more genetically different tissues, most commonly as a result of a graft and sometimes within the individual, by mutations and irregularities that occur during cell division.

  • chiropterophilous: pollinated by bats.

  • chlorophyll
    Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...

    : a green pigment in chloroplasts, essential for photosynthesis.

  • chloroplast
    Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis.Chloroplasts are green...

    : an organelle present in plant cells that contains chlorophyll.

  • cilia (singular cilium, adjective ciliate): generally, hairs more or less confined to the margins of an organ, like eye-lashes; in motile cells, minute, hair-like protrusions which aid motility.

  • circinate (circinnate): spirally coiled with the tip innermost; e.g. the developing fronds of most ferns.

  • cladode: a photosynthetic stem, often leaf-like and usually with foliage leaves either absent or much reduced; cf. phyllode.

  • class
    Class (biology)
    In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...

    : the principal category for taxa in a rank between division and order.

  • clathrate: latticed or pierced with apertures. In this structures, such as scales, this appearance is caused by thick cell walls between adjacent cells and thin cell walls on the sides of the cells that face the surfaces of the scale.

  • clavate: club-shaped.

  • claw: (1) narrow, stalk-like basal portion of petal, sepal of bract; (2) in Melaleuca, the united portion of a stamen bundle.

  • cleistogamous: of flowers that self-pollinate and never open fully, or self-pollinate before opening; cf. chasmogamous.

  • climber
    A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...

    : a plant growing more or less erect by leaning or twining on another structure for support.

  • cline (adjective clinal): continuous morphological variation in form within a species or sometimes between two species.

  • clone
    Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...

    : plants derived from the vegetative reproduction of an individual, all having the same genetic constitution.

  • coalescent
    Coalescent is a science-fiction novel by Stephen Baxter. It is part one of the Destiny's Children series, and is the first in the reading order for the Xeelee series...

    : plant parts fused or grown together to form a single unit.

  • coherent: (of like parts) sticking together, but not firmly or solidly as in connate.

  • colleter: a multicellular, glandular hair that usually produces a mucilaginous substance and is located on sepals, stipules, or petioles, or on nearby parts of stems; commonly found on plants in the order Gentianales.

  • columella
    Lucius Junius Moderatus Columella is the most important writer on agriculture of the Roman empire. Little is known of his life. He was probably born in Gades , possibly of Roman parents. After a career in the army , he took up farming...

    : in flowering plants, the central axis of the cone or fruit, e.g. in Callitris.

Column (botany)
The column, or technically the gynostemium, is a reproductive structure that can be found in several plant families: Aristolochiaceae, Orchidaceae, and Stylidiaceae....

: (1) structure extending above ovary and incorporating the style and stamens; gynostemium; e.g. in orchids; (2) in grasses, the lower, stouter, and usually twisted part of an awn, distinct from the slender upper part or bristle.
  • columnar
    In biology, columnar refers to the shape of epithelial cells that are taller than they are wide. Form follows function in biology, and columnar morphorphology hints at the functions of the cell. Columnar cells are important in absorption and movement of mucus...

    : shaped like a column.

  • commercial name: a name often of no botanical standing and not governed by the ICNCP. The term generally applies to names such as Trademark Names, names covered by Plant Breeders Rights, Patents and Promotional Names; often used to enhance the sale of a plant.

  • commissure
    A commissure is the place where two things are joined. The term is used especially in the fields of anatomy and biology.In anatomy, commissure refers to a bundle of nerve fibers that cross the midline at their level of origin or entry .* The most common usage of the term refers to the brain's...

    : the seam or face by which two carpels adhere.

  • community: an assemblage, in nature, of plants that characteristically occur together.

compound: composed of several parts, for instance a leaf with leaflets, a gynoecium with several carpels, or an inflorescence made up of smaller inflorescences.
  • compressed: flattened lengthwise, either laterally (from side to side) or dorsally (from front to back).

  • concolorous: the same colour throughout.

  • cone: a fruit, usually woody, ovoid to globular, including scales, bracts or bracteoles arranged around a central axis, e.g. in gymnosperms, especially conifers and Casuarina.

  • conflorescence: of an inflorescence when the overall structure substantially differs from that of its individual flowers; e.g. the bottlebrush multiple -flower head of callistemons.

  • connate
    Connation in plants is the developmental fusion of organs of the same type, for example, petals to one another to form a tubular corolla. This is in contrast to adnation, the fusion of dissimilar organs.-Terms for connation of flower parts:...

    : fused to another organ (or organs) of the same kind; e.g. petals in a floral tube; cf. adnate.

  • connective: the part of an anther that connects the anther cells.

  • connivent: coming into contact or converging.

  • conspecific: belonging to the same species.

  • contiguous: adjoining, touching, but not united.

  • contorted: twisted out of the normal shape.

  • convolute: referring to the arrangement of floral or foliar organs in a bud when each organ or segment has one edge overlapping the adjacent organ or segment; a form of imbricate arrangement; contorted.

  • cordate: heart-shaped, with the notch lowermost; of the base of a leaf, like the notched part of a heart.

  • coriaceous: leathery; stiff and tough, but somewhat flexible.

A corm is a short, vertical, swollen underground plant stem that serves as a storage organ used by some plants to survive winter or other adverse conditions such as summer drought and heat ....

: fleshy, swollen stem base, usually underground, storing food reserves, with buds naked or covered by very thin scales; a type of rootstock. Adjectives derived from "corm" include "cormose" and "cormous".
corolla: collective term for the petals of a flower.
  • corona (adjective: coronate): literally, crown; (1) in flowering plants, ring of tissue arising from the corolla or perianth of a flower and standing between the perianth lobes and the stamens; e.g. the daffodil trumpet, passionfruit; (2) in grasses, a hardened ring of tissue surmounting the lemma in some species.

  • corymb (adjective corymbose): inflorescence with branches arising at different points but reaching about the same height, giving the flower cluster a flat-topped appearance.

  • costa (adjective costate): a rib
    In vertebrate anatomy, ribs are the long curved bones which form the rib cage. In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax...


  • cotyledon
    A cotyledon , is a significant part of the embryo within the seed of a plant. Upon germination, the cotyledon may become the embryonic first leaves of a seedling. The number of cotyledons present is one characteristic used by botanists to classify the flowering plants...

    : primary leaf or leaves of an embryo, becoming the seed leaf or leaves.

  • crenate: with blunt or rounded teeth, scalloped.

  • crenulate: minutely scalloped.

  • crisped: finely curled. A term generally applied to the edges of leaves and petals.

Crown (botany)
The crown of a plant refers to the totality of the plant's aboveground parts, including stems, leaves, and reproductive structures. A plant canopy consists of one or more plant crowns growing in a given area....

: see canopy.
  • cross: to make something interbreed; the act of hybridization.

  • cruciform
    Cruciform means having the shape of a cross or Christian cross.- Cruciform architectural plan :This is a common description of Christian churches. In Early Christian, Byzantine and other Eastern Orthodox forms of church architecture this is more likely to mean a tetraconch plan, a Greek cross,...

    : cross-shaped.

  • crustaceous: hard, thin and brittle.

  • cryptogams
    The name cryptogams is used fairly widely as a phrase of convenience, although regarded as an obsolete taxonomic term. A cryptogam is a plant that reproduces by spores...

    : ferns, bryophytes, algae and fungi (including lichenized fungi); 'lower plants'; plants producing spores, and without stamens, ovaries or seeds, literally plants whose sexual reproductive organs are not conspicuous cf. phanerogam.

  • culm: in grasses, sedges, rushes, and some other monocotyledons, an aerial stem bearing the inflorescence; strictly, from the base of the plant to the lowest involucral bract (or base of the inflorescence).

  • cultigen
    A cultigen is a plant that has been deliberately altered or selected by humans; it is the result of artificial selection. These "man-made" or anthropogenic plants are, for the most part, plants of commerce that are used in horticulture, agriculture and forestry...

    : a plant whose origin or selection is primarily due to intentional human activity.

  • cultivar
    A cultivar'Cultivar has two meanings as explained under Formal definition. When used in reference to a taxon, the word does not apply to an individual plant but to all those plants sharing the unique characteristics that define the cultivar. is a plant or group of plants selected for desirable...

    : the term cultivar is derived from cultivated variety and denotes an assemblage of cultivated plants clearly distinguished by one or more characters (morphological, physiological, cytological, chemical or other); when reproduced (sexually or asexually), the assemblage retains its distinguishing characters. A cultivar may arise in cultivation or be introduced from the wild. It is a variant of horticultural interest or value. Cultivar names are written with single quotation marks around them e.g. 'Blue Carpet', 'Alba'. All new names established after 1 January 1959, must be in common language (that is, not in Latin) but names established in Latin prior to this date are retained in Latin form.

  • cultivar epithet: the defining part of a name that denominates a cultivar. Cultivars are designated by fancy (q.v.) epithets appended either to the scientific name or to the common name of the taxon to which they belong; they are not italicized but placed in single quotation marks, for example Rubus nitidoides 'Merton Early'. 'Merton Early' is the cultivar epithet.

  • cuneate: wedge-shaped; with straight sides converging at base. See Leaf shape
    Leaf shape
    In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...


  • cuspidate: tipped with a cusp.

  • cutting: a piece of plant, usually an apical tip of shoot structure but may be root or leaf, cut from plant and used for vegetative propagation.

  • cyathium
    A cyathium is one of the specialised pseudanthia forming the inflorescence of plants in the genus Euphorbia . A cyathium consists of:...

    : an inflorescence of unisexual flowers surrounded by involucral bracts, e.g. the flowers of Euphorbia.*

  • cyme (adjective cymose): inflorescence in which the main axis and all lateral branches end in a flower (each lateral may be repeatedly branched).

  • cypsela: a dry, indehiscent, one-seeded fruit formed from an inferior ovary.


Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

: falling seasonally, for instance bark, leaves, petals; persistent.
  • decorticate: to shed or peel off the outer bark of a tree.

  • decumbent: with branches growing horizontally but turned up at the ends.

  • decurrent
    Decurrent is a term used in botany and mycology to describe plant or fungal parts that extend downward.In botany, the term is most often applied to leaf blades that partly wrap or have wings around the stem or petiole and extend down along the stem...

    : extending downwards beyond the point of exsertion, e.g. when the base of a leaf is prolonged downwards along the stem in a raised line or narrow wing.

  • decussate: opposite, with successive pairs borne at right angles to the last; generally applied to the arrangement of leaves.

definite: of a constant number; e.g. twice as many stamens as the petals or sepals (or less), or an inflorescence ending in a flower or an aborted floral bud, typically a cymose inflorescence; cf. indefinite.
deflexed: bent downwards; compare inflexed.
  • dehiscent: breaking open at maturity to release contents. Generally refers to the release of seed from some fruits; also pollen from anthers.

  • deltoid
    Delta (letter)
    Delta is the fourth letter of the Greek alphabet. In the system of Greek numerals it has a value of 4. It was derived from the Phoenician letter Dalet...

    : with the shape of the Greek letter, i.e. like an equilateral triangle. See Leaf shape
    Leaf shape
    In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...


  • dendroid: tree-like, branching like a tree.

  • dentate: toothed. See Leaf margin.

  • denticulate: finely toothed.

  • determinate: limited, usually in growth.

  • dichasium: a cymose inflorescence with all branches below the terminal flower in regular opposite pairs; compare monochasium.

  • dichotomous: forking into two equal branches, resulting from an equal division of the growing tip.

The dicotyledons, also known as dicots, are a group of flowering plants whose seed typically has two embryonic leaves or cotyledons. There are around 199,350 species within this group...

: a flowering plant whose embryo has two (rarely more) cotyledons (seed leaves) (common usage: dicot.) compare monocotyledon (common usage: monocot.).
  • digitate: with segments spreading from a common centre, like the fingers of a hand; see also palmatisect.

  • dimorphic (dimorphous): of 2 different kinds (in respect to shape and/or size), for example of stamens, fronds
    Frond dimorphism
    Frond dimorphism refers to a difference in ferns between the fertile and sterile fronds. Since ferns, unlike flowering plants, bear spores on the leaf blade itself, this may affect the form of the frond itself...

    , leaves.

  • dioecious
    Dioecy is the property of a group of biological organisms that have males and females, but not members that have organs of both sexes at the same time. I.e., those whose individual members can usually produce only one type of gamete; each individual organism is thus distinctly female or male...

    : of plant, when male and female reproductive structures develop on different individuals; of infloresence, male and female flowers in separate infloresences; cf. monoecious.

  • diploid: with two full sets of chromosomes in the nucleus of a cell; having two complements of haploid chromosomes, that is the two complete sets of chromosomes, one from each of the parental gamete. This is expressed symbolically as 2n, where n = the gamete number of chromosomes.

  • disk (disc): a plate or ring of structures derived from the receptacle, and occurring between whorls of floral parts: in daisies, the central part of capitulum, hence disk flowers or florets.

  • discolorous: of leaves, with upper and lower surfaces of a different colour.

  • disjunct
    Disjunct distribution
    In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but widely separated from each other geographically...

    : occurring in widely separated geographic areas, distinctly separate; applies to a discontinuous range in which one or more populations are separated from other potentially interbreeding populations far enough as to preclude gene flow between them.

  • dissected: deeply divided; cut into many segments.

  • distal: remote from the point of origin or attachment; the free end; cf. proximal.

  • distichous: arranged in two opposite rows (and hence in the same plane).

  • distinct: separate or free, not united.

  • diurnal: of the day; occurring or opening in the daytime.

  • divaricate
    Divaricate is a term used in identifying plants describing the pattern of branching. Divaricate branching is roughly horizontal, usually only diverging about 15 degrees upward or downward....

    : wide-spreading.

  • divergent: spreading in different directions, generally upward.

  • division: the term used for the rank below kingdom in the taxonomic hierarchy.

  • domatia
    Domatia are tiny chambers produced by plants that house arthropods.Domatia differ from galls in that they are produced by the plant rather than being induced by their inhabitants...

    : pits formed at the junction of two veins on the undersurface of leaves (mostly of rainforest plants); often modified appendages that shelter parasites and other micro-organisms.

dorsal: the back; at the back; in particular, away from the axis in a lateral organ or away from the substratum in a prostrate plant.
  • dorsifixed: attached at or by the back, e.g. anthers on a filament.

  • dorsiventral
    Dorsiventral is a term used to describe an organ which has two surfaces differing from each other in appearance and structure, as an ordinary leaf. In biology, this term also refers to that which extends from a dorsal to a ventral surface....

    : having structurally different upper and lower surfaces, e.g. some leaves.

In botany, a drupe is a fruit in which an outer fleshy part surrounds a shell of hardened endocarp with a seed inside. These fruits develop from a single carpel, and mostly from flowers with superior ovaries...

: a succulent fruit formed from one carpel; the single seed is enclosed by a stony layer of the fruit wall; kernel; e.g. peaches, olives and the fruit of Nitraria billardieri.


  • ecological amplitude: the range of environmental conditions in which an organism can survive.

  • elaisome: oily body attached to the seed.

  • ellipsoid: a 3-dimensional shape, elliptical in all sections through the long-axis.

elliptical (elliptic): planar, shaped like a flattened circle, symmetrical about both the long and the short axis; about twice as long as broad, tapering equally both to the tip and the base; oval.
  • emarginate: notched at apex (notch usually broad and shallow).

  • embryo
    An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...

    : young plant contained by a seed.

  • enantiostyly: the condition in which the gynoecium protrudes laterally, to the right (dextrostyly) or to the left (sinistrostyly) of the androecium. example: Senna

  • endemic: having a natural distribution restricted to a particular geographic region; cf. native.

  • endocarp: the innermost layer of the wall of a fruit; in a drupe, the stony layer surrounding the seed.

  • endosperm
    Endosperm is the tissue produced inside the seeds of most flowering plants around the time of fertilization. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This makes endosperm an important source of nutrition in human diet...

    : nutritive tissue in a seed; albumen.

  • ensiform: shaped like the blade of a sword.

  • entire: having a smooth margin, not lobed, divided or toothed (it may be wavy or scalloped, but not incised).

  • ephemeral
    Ephemeral things are transitory, existing only briefly. Typically the term is used to describe objects found in nature, although it can describe a wide range of things....

    : short-lived.

  • epicalyx: an involucre resembling an outer calyx; e.g. as seen in Hibiscus.

  • epicarp: the outer layer of the wall of a fruit, i.e. the 'skin'.

  • epicormic: said of buds shoots or flowers developing from the old wood of trees, especially after injury or fire.

  • epicotyl
    In plant physiology, the epicotyl is the embryonic shoot above the cotyledons. In most plants the epicotyl will eventually develop into the leaves of the plant. In dicots, the hypocotyl is what appears to be the base stem under the spent withered cotyledons, and the shoot just above that is the...

    : the part of the plant axis or stem between the cotyledonary node and first foliage leaves.

  • epidermis
    Epidermis (botany)
    The epidermis is a single-layered group of cells that covers plants' leaves, flowers, roots and stems. It forms a boundary between the plant and the external environment. The epidermis serves several functions, it protects against water loss, regulates gas exchange, secretes metabolic compounds,...

    : an organ's outermost layer of cells, usually only one cell thick.

  • epigynous: borne on the ovary; describes floral parts when attached above the level of the ovary and arising from tissue fused to the ovary wall; cf. hypogynous, perigynous.*

epilithic: see lithophytic.
  • epipetalous: of stamens that are attached to the petals.

  • epiphytic: see lithophytic.

  • epitepalous: of stamens that are attached to the tepals.

An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...

(adjective epiphytic): one plant growing on another without deriving nourishment from it (in other words, not parasitic); compare parasite. Loosely, and incorrectly, applied to plants that are not terrestrial (they may grown on various inorganic or organic surfaces), and often to orchids, which are rock-dwelling (and therefore strictly lithophytic).
  • epithet
    An epithet or byname is a descriptive term accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, divinities, objects, and binomial nomenclature. It is also a descriptive title...

    : the adjectival component in a binomial; final word or combination of words in a name of more than one word (other than a term denoting rank) that denominates an individual taxon.

  • equitant: of a leaf when folded lengthwise with edges adhering except at the base, where it clasps another leaf on the opposite side of the stem.*

erect: upright, more or less perpendicular to the ground or point of attachment.
  • ericoid: with leaves like the European heath (Erica), small and sharply pointed.

  • erose: with the margin irregular as though nibbled or worn away.

  • even-pinnate: having an even number of leaflets in a compound leaf, = paripinnate.

  • evergreen
    In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

    : not deciduous, having leaves all the year round.

  • ex: in nomenclature, indicating that the preceding author proposed the name but did not legitimately publish it, and that the succeeding author referred to the first author when legitimately publishing the name. See Author citation (botany)
    Author citation (botany)
    In botanical nomenclature, author citation refers to citing the person who validly published a botanical name, i.e. who first published the name while fulfilling the formal requirements as specified by the International Code of Botanical Nomenclature...


  • exocarp: the outer layer of the pericarp, often the skin of fleshy fruits.

  • exotic
    Introduced species
    An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

    : not native; introduced from another region or country.

  • exserted: projected beyond, e.g. the stamens beyond the corolla tube.

  • exstipulate: without stipules.

  • extrastaminal: outside the stamens or androecium, usually referring to the location of a nectary disk.

  • extrorse: of anther locules, opening towards the outside of the flower; cf. introrse, latrorse.


  • F1 hybrid
    F1 hybrid
    F1 hybrid is a term used in genetics and selective breeding. F1 stands for Filial 1, the first filial generation seeds/plants or animal offspring resulting from a cross mating of distinctly different parental types....

    : a single cross; a plant breeding term for the result of a repeatable cross between two pure bred lines.

  • F2 hybrid: a plant breeding term for the result of a plant arising from a cross between two F1 hybrids; may also refer to self-pollination in a population of F1 hybrids.

Facultative means "optional" or "discretionary" , used mainly in biology in phrases such as:* Facultative anaerobe, an organism that can use oxygen but also has anaerobic methods of energy production...

: of parasites, optional; compare obligate.
  • falcate: curved like the blade of a scythe.

Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

: a formal group of one or more genera with features and/or ancestry in common; the term for the principal rank between order and genus.
  • fascicle
    Fascicle (botany)
    In botany, a fascicle is a bundle of leaves or flowers, or of the vascular tissues that supply these organs with nutrients...

    : (adjective fasciculate) cluster, e.g. a tuft of leaves all arising from the same node.

  • fastigiate: parallel, clustered and erect, e.g. the arrangement of branches in the Lombardy Poplar.

  • felted: covered with very dense, interlocked and matted hairs with the appearance or texture of felt or woollen cloth.

  • ferruginous: rust
    Rust is a general term for a series of iron oxides. In colloquial usage, the term is applied to red oxides, formed by the reaction of iron and oxygen in the presence of water or air moisture...


  • fertile
    The term fertile describes a condition whereby organisms are able to produce physically healthy offspring.Fertile may also refer to:...

    : capable of producing fruit; of flowers when they produce seed or of anthers containing pollen.

  • fertilization: union of male and female gametes.

filament: (1) stalk of a stamen; (2) thread, one or a few cells thick.
  • filamentous: consisting of filaments or fibres.

  • filiform: thread-like. See Leaf shapes.

  • fimbriate: fringed.

  • fissure
    In anatomy, a fissure is a groove, natural division, deep furrow, elongated cleft, or tear in various parts of the body.-Brain:...

    : a split or crack, often referring to fissured bark. also, a line or opening of dehiscence.

  • flabellate: fan-shaped.

flaccid: limp; tending to wilt; compare turgid.
  • flexuous (flexuose): bent alternately in different directions; zig-zag.

  • floccose: with a soft and woolly covering of hairs.

  • flora
    Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animals is fauna.-Etymology:...

    : (1) all the plants growing in a certain region or country; (2) an enumeration of them, generally with a guide to their identification (e.g. the present volume, the Flora of Victoria, the Flora of New South Wales and so on). In this case 'flora' is written with a capital F.

  • floral leaves: the upper leaves at the base of the flowering branches.

floral tube: tube bearing the perianth and stamens, consisting of tissue derived from the receptacle and/or perianth and/or stamens; hypanthium.
floret: a small flower; usually refers to the flowers of the daisy and grass families.
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...

: the sexual reproductive structure of the angiosperms, typically with a gynoecium, androecium, perianth and an axis.
  • follicle
    Follicle (fruit)
    In botany, a follicle is a dry unilocular many-seeded fruit formed from one carpel and dehiscing by the ventral suture in order to release seeds, such as in larkspur, magnolia, banksia, peony and milkweed....

    : a dry fruit formed from one carpel, splitting along a single suture, to which the seeds are attached; cf. pod (of legume).

  • forest
    A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

    : vegetation dominated by trees with single trunks (including closely arranged trees with or without an understorey of shrubs and herbs).

  • forma (in common usage, form
    Form (botany)
    In botanical nomenclature, a form is one of the "secondary" taxonomic ranks, below that of variety, which in turn is below that of species; it is an infraspecific taxon...

    ): a taxonomic category subordinate to species and within the taxonomic hierarchy, below variety (varietas), usually differentiated by a minor character.

  • free: not united with others organs of the same type; not attached at one end.

  • free central: of placentation, ovules attached to a free-standing column in the centre of a unilocular ovary.

  • frond
    The term frond refers to a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group...

    : a leaf of a fern, cycad or palm.

  • fruit
    In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

    : seed-bearing structure in angiosperms formed from the ovary, and sometimes associated floral parts, after flowering.

  • funicle (funiculus): the stalk of an ovule.

  • funnelform: with a form gradually widening from the base to apex; funnel-shaped.

  • fused: joined together.

  • fusiform: 3-dimensional, narrowing gradually from the middle towards each end; spindle-shaped.


  • galbulus: (in gymnosperms) a fleshy cone (megastrobilus); chiefly relates to those borne by junipers and cypresses and often mistakenly called berries.

  • gamete
    A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...

    : (in ferns, gymnosperms and angiosperms) a cell or nucleus that fuses with another of the opposite sex in sexual reproduction.

  • gametophyte
    A gametophyte is the haploid, multicellular phase of plants and algae that undergo alternation of generations, with each of its cells containing only a single set of chromosomes....

    : plant that bears gametes; in ferns, usually a small but discrete plant very different from the sporophyte (which is normally considered the fern plant); in gymnosperms and angiosperms, a microscopic structure (part of the reproductive apparatus) not recognizable as a discrete plant.

  • gene pool
    Gene pool
    In population genetics, a gene pool is the complete set of unique alleles in a species or population.- Description :A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can survive bouts of intense selection...

    : the range of genetic variation found in a population.

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

(plural genera): a group of one or more species with features or ancestry (or both) in common. Genus is the principal category of taxa intermediate in rank between family and species in the nomenclatural hierarchy.
  • generic name: the name of a genus, for example Acacia
    Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...

    , Eucalyptus
    Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...


  • genotype
    The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...

    : the genetic make-up of an individual.

  • germination
    Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...

    : (1) of seeds, describing the complex sequence of physiological and structural changes that occur from resting to growth stage. (2) of a pollen grain; production of a pollen tube when contacting a stigma receptive to it; (3) of a spore of fungi/bacterium; change of state – from resting to vegetative.

  • gibbous (gibbose): when part of an organ is swollen; usually with a pouch-like enlargement at base.

  • glabrescent: becoming glabrous, almost glabrous.

  • glabrous: without surface ornamentation such as hairs, scales or bristles.

  • gland
    Gland (botany)
    In plants, a gland is defined functionally as a plant structure which secretes one or more products. This may be located on or near the plant surface and secrete externally, or be internal to the plant and secrete into a canal or reservoir...

    : a secretory structure within or on the surface of a plant; (loosely) a smooth, usually shining, bead-like outgrowth.

  • glandular hair: hairs tipped with a gland.

  • glaucous
    Glaucous is used to describe the pale grey or bluish-green appearance of the surfaces of some plants, as well as in the names of birds, such as the Glaucous Gull , Glaucous-winged Gull , Glaucous Macaw , and Glaucous...

    : with a whitish bloom, blue-green in colour; e.g. the surface of the young leaves of many eucalypts.

  • globose (globular): nearly spherical.

  • globulose: small or nearly spherical.

  • glochid
    Glochids are hair-like spines or short prickles, generally barbed, found on the areoles of cacti in the sub-family Opuntioideae. Cactus glochids easily detach from the plant and lodge in the skin, causing irritation upon contact...

    : a barbed hair or bristle, e.g. the fine hairs in Opuntia.

  • glumes: bracts subtending the floret(s) of a sedge, or similar plant; in grasses forming the lowermost organs of a spikelet (there are usually 2 but 1 is sometimes reduced; or rarely, both are absent).

  • glutinous: sticky.

  • graft
    Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. This vascular joining is called inosculation...

    : (1) of a plant, the artificial union of plant parts; (2) a plant shoot suitable for grafting; loosely means a scion, sucker, or branch; (3) an old word for a spade's depth of soil; (4) a kind of spade used for digging drains.

  • graft chimaera, sometimes called a graft hybrid: a taxon whose members consist of tissue from two or more different plants in intimate association originated by grafting. The addition sign "+" is used to indicate a graft-chimaera either as a part of a formula (e.g. Crataegus monogyna + Mespilus germanica), or in front of an abbreviated name (e.g. +Crataegomespilus
    +Crataegomespilus is the generic name applied to graft-chimeras between the genera Crataegus and Mespilus. It is not to be confused with ×Crataemespilus, which is applied to sexual hybrids between those genera, nor with Chamaemespilus which is a segregate genus or subgenus of Sorbus....

     'Dardari'). The nomenclature of graft hybrids is governed by the International Code of Nomenclature for Cultivated Plants
    International Code of Nomenclature for Cultivated Plants
    The International Code of Nomenclature for Cultivated Plants regulates the names of cultigens...


  • granular: of a surface, covered with small rounded protuberances.

  • grass
    Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

    : a plant belonging to the family Poaceae.

  • grassland
    Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...

    : low vegetation dominated by grasses.

  • groundcover
    Groundcover refers to any plant that grows over an area of ground, used to provide protection from erosion and drought, and to improve its aesthetic appearance .- Ecosystem :...

    : (1) of a plant, with a very flat and soil-hugging habit; (2) a term applied to describe a plant that covers the soil surface so densely that it smothers all beneath it.

  • Group
    Cultivar group
    In naming cultivated plants, a Group is a formal classification category, under the International Code of Nomenclature for Cultivated Plants :The term "Group" was introduced in the 2004 ICNCP, replacing the "Cultivar-group" of the 1995 ICNCP.A Group is united by some common trait; for example...

    : a formal category equivalent to or below the rank of genus. It distinguishes: (1) an assemblage of two or more cultivars within a species or hybrid; (2) plants derived from a hybrid in which one or more of the parent species is not known or is of uncertain origin; and (3) a range of cultivated plants of a species or hybrid which may exhibit variation but share one or more characters, which makes it worth distinguishing them as a unit.

  • gymnosperm
    The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...

    : a seed-bearing plant with ovules borne on the surface of a sporophyll; includes, among others, conifers, Ginkgo
    Ginkgo , also spelled gingko and known as the Maidenhair Tree, is a unique species of tree with no close living relatives...

    , Gnetum
    Gnetum is a genus of about 30-35 species of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms they possess vessel elements in the xylem...

    and cycads.

  • gynobasic: of a style, arising near the base of the gynoecium, e.g. between the lobes of the ovary.

  • gynoecium
    Gynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...

    : female parts of flower; the collective term for the carpels of a flower whether united or free; cf. pistil; androecium.

  • gynophore
    A gynophore is the stalk of certain flowers which supports the gynoecium , elevating it above the branching points of other floral parts....

    : stalk supporting the gynoecium (above the level of insertion of the other floral parts).


  • habit
    Habit (biology)
    Habit, when used in the context of biology, refers to the instinctive actions of animals and the natural tendencies of plants.In zoology, this term most often refers to specific behavioral characteristics, even when directly related to physiology...

    : the general external appearance of a plant, including size, shape, texture and orientation.

  • habitat
    * Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

    : the place where a plant lives; the environmental conditions of its home.

  • hair
    Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....

    : a single elongated cell or row of cells borne on the surface of an organ.

half-inferior: of ovary, partly below and partly above the level of attachment of the other floral parts; compare inferior, superior.
  • halophyte
    A halophyte is a plant that grows where it is affected by salinity in the root area or by salt spray, such as in saline semi-deserts, mangrove swamps, marshes and sloughs, and seashores. An example of a halophyte is the salt marsh grass Spartina alterniflora . Relatively few plant species are...

    : a plant adapted to living in highly saline habitats; a plant that accumulates high concentrations of salt in its tissues.

  • hand-pollination: the controlled act of pollination that excludes the possibility of open-pollination.

  • haploid: of chromosomes, and relative to the phase of an alternation of generations in which the duplicated chromosome set or diploid condition is reduced; the condition when the chromosomes are not duplicated, e.g. the complement of chromosomes in the nucleus of a gamete; a single basic set of chromosomes in the nucleus of a cell. This may be expressed symbolically as n, where n = the gamete number of chromosomes.

  • hastate: like the head of a halbert, i.e. narrow and pointed but abruptly enlarged at the base into two acute diverging lobes; may refer only to the base of a leaf with such lobes; cf. sagittate.

  • haustorium
    In botany, a haustorium is the appendage or portion of a parasitic fungus or of the root of a parasitic plant that penetrates the host's tissue and draws nutrients from it. Haustoria do not penetrate the host's cell membranes.Fungi in all major divisions form haustoria...

    : in parasitic plants, a structure developed for penetrating the host's tissues.

Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....

: see capitulum.
  • heathland: vegetation dominated by small shrubs which usually have ericoid leaves.

  • helicoid
    The helicoid, after the plane and the catenoid, is the third minimal surface to be known. It was first discovered by Jean Baptiste Meusnier in 1776. Its name derives from its similarity to the helix: for every point on the helicoid there is a helix contained in the helicoid which passes through...

    : coiled; of a cymose inflorescence, when the branching is repeatedly on the same side (the apex is often recurved); cf. scorpioid.

  • herb
    Except in botanical usage, an herb is "any plant with leaves, seeds, or flowers used for flavoring, food, medicine, or perfume" or "a part of such a plant as used in cooking"...

    : a vascular plant that does not develop a woody stem; e.g. a violet.

  • herbaceous
    A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...

    : not woody; usually green, and soft in texture.

  • herbarium
    In botany, a herbarium – sometimes known by the Anglicized term herbar – is a collection of preserved plant specimens. These specimens may be whole plants or plant parts: these will usually be in a dried form, mounted on a sheet, but depending upon the material may also be kept in...

    : a collection of preserved, usually dried, plant material. Also a building in which such collections are stored.

  • hermaphrodite
    In biology, a hermaphrodite is an organism that has reproductive organs normally associated with both male and female sexes.Many taxonomic groups of animals do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both...

    : see bisexual.

  • heteromorphic: of 2 or more distinct morphologies (e.g. of different size and shape).

  • hilum
    Hilum (biology)
    In botany, the hilum is a scar or mark left on a seed coat by the former attachment to the ovary wall or to the funiculus...

    : the scar on a seed coat where it separates from its stalk (funicle).

  • hip
    Rose hip
    The rose hip, or rose haw, is the fruit of the rose plant, that typically is red-to-orange, but ranges from dark purple to black in some species. Rose hips begin to form in spring, and ripen in late summer through autumn.-Usage:...

    : the fruit of a rose.

  • hippocrepiform: horseshoe-shaped.

  • hirsute: bearing coarse, rough, longish hairs. See Indumentum
    The indumentum is a covering of fine hairs or bristles on a plant or insect.In plants, the indumentum types are:*pubescent*hirsute*pilose*villous*tomentose*stellate*scabrous*scurfy...


  • hispid: having long erect rigid hairs or bristles, harsh to touch.

  • hoary: covered with a greyish to whitish layer of very short, closely interwoven hairs, giving a frosted appearance.

  • holotype
    A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

    : a type chosen by the author of a name; cf. a lectotype, which is chosen by a later author.

  • hort.: (never capiltalised) of gardens, an author citation used in two ways: (1) as a name misapplied by gardeners and (2) as an invalid name derived from horticultural writings of confused authorship.

  • hyaline
    The term hyaline denotes a substance with a glass-like appearance.-Histopathology:In histopathological medical usage, a hyaline substance appears glassy and pink after being stained with haematoxylin and eosin — usually it is an acellular, proteinaceous material...

    : translucent; usually delicately membranous and colourless.

  • hybrid: a plant produced by the crossing of parents belonging to two different named groups, e.g. genera, species, varieties, subspecies, forma and so on; i.e. the progeny resulting within and between two different plants. An F1 hybrid is the primary product of such a cross. An F2 hybrid is a plant arising from a cross between two F1 hybrids (or from the self-pollination of an F1 hybrid).

  • hybrid formula: the names of the parents of a hybrid joined by a multiplication sign, e.g. Cytisus ardonoi × C. purgans.

  • Hydrophily
    Hydrophily is a fairly uncommon form of pollination whereby pollen is distributed by the flow of waters, particularly in rivers and streams. Hydrophilous species fall into two categories: those that distribute their pollen to the surface of water, and those that distribute it beneath the...

    : a fairly uncommon form of pollination whereby pollen is distributed by the flow of waters.

  • hypanthium
    A hypanthium is a floral structure consisting of the bases of the sepals, petals, and stamens fused together. Its presence is diagnostic of many families, including the Rosaceae, Grossulariaceae, and Fabaceae...

    : see floral tube.

  • hypogynous: borne below the ovary; used to describe floral parts inserted below the ovary's level of insertion; cf. epigynous, perigynous.

  • hypocotyl
    The hypocotyl is the stem of a germinating seedling, found below the cotyledons and above the radicle .-Dicots:...

    : of an embryo or seedling, the part of the plant axis below the cotyledon and node, but above the root. It marks the transition from root to stem development.


  • illegitimate name (nomen illegitimum
    Nomen illegitimum
    A nomen illegitimum is a technical term, used mainly in botany. It is usually abbreviated as nom. illeg..-Definition:...

    ): a name not abiding by the rules of the botanical Codes, e.g. cultivars that have been Latinised after 1 Jan 1959; cultivar names with more 10 syllables or 30 letters; cultivar names that use confusing names of other plants, e.g. Camellia 'Rose'.

imbricate: overlapping each other; of perianth parts, edges overlapping in the bud (the convoluted arrangement is a special form of imbrication).
imparipinnate: a pinnate leaf with an odd number of pinnae (terminated by a single leaflet); compare paripinnate.
  • in: in nomenclature, where the preceding author published the name in an article or book, authored or edited by the succeeding author.

  • inbreeding
    Inbreeding is the reproduction from the mating of two genetically related parents. Inbreeding results in increased homozygosity, which can increase the chances of offspring being affected by recessive or deleterious traits. This generally leads to a decreased fitness of a population, which is...

    : the production of offspring between closely related parents leading to a high degree of similarity; self-fertilization is the most intense form of inbreeding.

  • incised
    Incised means cut, particularly with a "V" shape. It is a term found in a number of disciplines.-Geology: In geomorphology, the term Incised refers to when a river has cut downward through its riverbed. The river may have been incising through sediment or bedrock. The river begins at one elevation...

    : cut deeply and (usually) unevenly (a condition intermediate between toothed and lobed).

  • included: enclosed, not protruding; for example stamens within the corolla.

  • incurved: bent or curved inwards; of leaf margins, when curved towards the adaxial side.

indefinite: variable in number; numerous; e.g. more than twice as many stamens as petals or sepals, or when an inflorescence is not terminated by a flower (and continues growing); cf. definite.
  • indehiscent: not opening in any definite manner at maturity; usually referring to fruit.

  • indeterminate
    Indeterminate growth
    In biology and especially botany, indeterminate growth refers to growth that is not terminated in contrast to determinate growth that stops once a genetically pre-determined structure has completely formed. Thus, a plant that grows and produces flowers and fruit until killed by frost or some other...

    : unlimited, usually in growth.

  • indigenous
    Indigenous (ecology)
    In biogeography, a species is defined as native to a given region or ecosystem if its presence in that region is the result of only natural processes, with no human intervention. Every natural organism has its own natural range of distribution in which it is regarded as native...

    : native to the area, not introduced, and not necessarily confined to the region discussed or present throughout it (hardly distinct from ‘native’ but usually applied to a smaller area). For example, the Cootamundra Wattle is native to Australia but indigenous to the Cootamundra region of southern New South Wales; cf. endemic.

  • indumentum
    The indumentum is a covering of fine hairs or bristles on a plant or insect.In plants, the indumentum types are:*pubescent*hirsute*pilose*villous*tomentose*stellate*scabrous*scurfy...

    : any surface covering, e.g. hairs, scales; a collective term for such coverings.

  • indusium: (1) a membrane covering the sporangia of some ferns; (2) a cup enclosing the stigma in Goodeniaceae.

inferior: of an ovary, at least partly below the level of attachment of other floral parts; compare superior.
  • inflated: swollen, like a bladder.

inflexed: bent sharply upwards or forwards; compare deflexed.
  • inflorescence
    An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

    : several flowers closely grouped together to form an efficient structured unit; the grouping or arrangement of flowers on a plant.

  • infraspecific: denotes taxonomic ranks below species level, for example subspecies.

  • infructescence
    Infructescence is defined as the ensemble of fruits derived from ovaries of an inflorescence, structured according to the inflorescence scheme....

    : the grouping or arrangement of fruits on a plant.

  • infundibular (infundibularform): funnel-shaped.

  • inrolled: rolled inwards.

  • insectivorous: catching, and drawing nutriment from, insects.

  • integument: in general, any covering, but especially the covering of an ovule.

  • interjugary glands: in pinnate leaves, glands occurring along the leaf rachis between the pinnae (occurring below the single, and often slightly larger, gland at or just below the insertion of the pinnae); cf. jugary.

  • internode: the portion of a stem between two nodes.

  • interpetiolar: of stipules, between the petioles of opposite leaves.

  • intramarginal: inside but close to the margin, for example a vein in a leaf.

  • intrastaminal: inside the stamens or androecium, usually referring to the location of a nectary disk.

  • introrse: of anther locules, with opening towards the centre of flower (at least in bud); cf. extrorse, latrorse.

  • invalid: use of names not validly published according to the Code; i.e. they are not strictly 'names' in the sense of the International Code of Botanical Nomenclature.

  • involucre: a group of bracts surrounding the base of a flowerhead; e.g. as seen in a daisy.

involute: rolled inwards, for example when the margins of a leaf are rolled towards the adaxial (usually upper) surface; compare revolute.
irregular: cannot be divided into two equal halves through any vertical plane; compare zygomorphic, actinomorphic, regular.
  • isobifacial: (of flat structures, especially leaves) with both surfaces similar, usually referring to cell types or to the number and distribution of stomata.


  • joint: a node or junction of two parts; articulation.

  • jugary: of glands, gland occurring on the rachis of a bipinnate leaf at the junction or attachment of pairs of pinnae or pinnules, as in some Acacia species; cf. interjugary.

  • juvenile leaves: formed on a young plant and different in form from the adult leaves.


keel: a ridge like the keel of a boat, e.g. the structure formed by the fusion of the two anterior petals of a flower in the Fabaceae.
  • kernel: see drupe.

  • kingdom
    Kingdom (biology)
    In biology, kingdom is a taxonomic rank, which is either the highest rank or in the more recent three-domain system, the rank below domain. Kingdoms are divided into smaller groups called phyla or divisions in botany...

    : the highest generally employed category of the taxonomic hierarchy, above that of division (phylum).


  • labellum
    Labellum is the Latin diminutive of labium, meaning lip. These are anatomical terms used descriptively in biology, for example in Entomology and botany.-Botany:...

    : lip; one of three or five petals which is (usually) different from the others, e.g. in Orchidaceae and Stylidiaceae.

  • labiate: lipped; where the limb of a corolla is divided into two parts, called an upper and lower lip, the two resembling an open mouth with lips.

  • lacerate: jagged, as if torn.

  • laciniate: slashed into narrow, pointed lobes.

  • lamella (plural lamellae, adjective lamellate): a thin, plate-like layer.

  • lamina: the blade of a leaf or the expanded upper part of a petal, sepal or bract.

  • lanceolate: about four times as long as broad, broadest in the lower half and tapering to the tip; narrowly ovate (sometimes, and incorrectly, used to mean narrowly elliptic; like a lance head).

  • lateral: attached to the side of an organ, e.g. leaves on a stem.

  • latex
    Latex is the stable dispersion of polymer microparticles in an aqueous medium. Latexes may be natural or synthetic.Latex as found in nature is a milky fluid found in 10% of all flowering plants . It is a complex emulsion consisting of proteins, alkaloids, starches, sugars, oils, tannins, resins,...

    : a milky substance that exudes from such plants such as milk thistles, figs and dandelions.

  • latrorse: a type of anther dehiscence in which the anthers open laterally toward adjacent anthers. cf. introrse, extrorse

  • lax: loose, not compact.

  • leaf
    A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....

    : an outgrowth of a stem, usually flat and green; its main function is food manufacture by photosynthesis.

leaflets: the ultimate segments of a compound leaf.
legume: (1) a fruit characteristic of the families Mimosaceae, Caesalpiniaceae and Fabaceae, formed from one carpel and either dihiscent along both sides, or indehiscent; (2) a crop species in the family Fabaceae; (3) a plant belonging to the Leguminosae (Fabaceae family).
  • lemma
    Lemma (botany)
    Lemma is a phytomorphological term used in botany referring to a part of the spikelet of grasses . It is the lowermost of two chaff-like bracts enclosing the grass floret. It often bears a long bristle called an awn, and may be similar in form to the glumes - chaffy bracts at the base of each...

    : the lower of 2 bracts enclosing a grass flower.

  • lenticel
    A lenticel is an airy aggregation of cells within the structural surfaces of the stems, roots, and other parts of vascular plants. It functions as a pore, providing a medium for the direct exchange of gasses between the internal tissues and atmosphere, thereby bypassing the periderm, which would...

    : a loosely packed mass of cells in the bark of a woody plant (used for gas exchange), visible on the surface as a raised powdery spot.

  • lepidote: covered with small scurfy scales.

  • liana
    A liana is any of various long-stemmed, woody vines that are rooted in the soil at ground level and use trees, as well as other means of vertical support, to climb up to the canopy to get access to well-lit areas of the forest. Lianas are especially characteristic of tropical moist deciduous...

    : a woody climbing plant, rooted in the ground (both liane and liana are used).

  • liane
    Liane is a female given name and may refer to one of the following;* Liane Bahler, German professional racing cyclist;* Liane Balaban, Canadian actress;* Liane Berkowitz, member of the German resistance movement during World War II;...

    : a woody climbing plant, rooted in the ground.

  • lignotuber
    A lignotuber is a starchy swelling of the root crown possessed by some plants as a protection against destruction of the plant stem by fire. The crown contains buds from which new stems may sprout, and a sufficient store of nutrients to support a period of growth in the absence of...

    : a woody swelling of the stem below or just above the ground; contains adventitious buds from which new shoots can develop, e.g. after fire.

  • ligulate: (1) bearing a ligule; (2) strap-shaped.

  • ligule
    A ligule — is a thin outgrowth at the junction of leaf and leafstalk of many grasses and sedges or a strap-shaped corolla, such as that of a ray floret in plants in the daisy family....

    : (1) small membranous appendage on the top of the sheath of grass leaves; (2) a minute adaxial appendage near the base of a leaf, e.g. in Selaginella; (3) extended, strap-like corolla of some daisy florets.

  • linear: very narrow in relation to its length, with the sides mostly parallel. See Leaf shape
    Leaf shape
    In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...


lithophytic: growing on rocks; epilithic.
  • lobe
    Lobe (anatomy)
    In anatomy, a lobe is a clear anatomical division or extension that can be determined without the use of a microscope This is in contrast to a lobule, which is a clear division only visible histologically....

    : part of a leaf (or other organ), often rounded, formed by incisions to about halfway to the midrib.*

  • loculicidal: of a fruit, when it dehisces through the centres of loculi; cf. septicidal.

  • loculus: a chamber or cavity, for example, within an ovary.

  • lomentum: a pod-like indehiscent fruit that develops constrictions between the segments and at maturity breaks into one-seeded segments.

  • lunate
    Lunate is a term meaning crescent or moon-shaped. In the specialized terminology of lithic reduction, a lunate flake is a small, crescent-shaped flake removed from a stone tool during the process of pressure flaking....

    : crescent-shaped.

  • lyrate: lyre-shaped; deeply lobed, with a large terminal lobe and smaller lateral ones.


  • Macaronesia
    Macaronesia is a modern collective name for several groups of islands in the North Atlantic Ocean near Europe and North Africa belonging to three countries: Portugal, Spain, and Cape Verde...

    : a biogeographic area encompassing the islands off the coast of NW Africa and Europe, including the Azores, Canaries, Cape Verde Islands and Madeira.

  • Malaysia: Malay peninsula and North Borneo.

  • Malesia
    Malesia is a biogeographical region straddling the boundaries of the Indomalaya ecozone and Australasia ecozone, and also a phytogeographical floristic region in the Paleotropical Kingdom.-Floristic province:...

    : a biogeographic region comprising Malaysia, Indonesia, New Guinea, and the Philippines.

  • mallee
    Mallee (habit)
    Mallee is the growth habit of certain eucalypt species that grow with multiple stems springing from an underground lignotuber, usually to a height of no more than ten metres...

    : growth habit in which several woody stems arise separately from a lignotuber; a plant with such a growth habit; vegetation characterized by such plants.

  • mangrove
    Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...

    : a shrub or small tree growing in salt or brackish water, usually characterized by pneumatophores.

margin: the edge, as in the edge of a leaf blade.
  • marginal: occurring at or very close to the margin.

  • marsh
    In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....

    : a waterlogged area; swamp.

  • mast
    Mast (botany)
    Mast is the "fruit of forest trees like acorns and other nuts". It is also defined as "the fruit of trees such as beech, and other forms of Cupuliferae". Alternatively, it can also refer to "a heap of nuts"....

    : the edible vegetative or reproductive part produced by woody species of plants, i.e. trees and shrubs, that wildlife species and some domestic animals consume.

  • mealy: covered with coarse, floury powder, sometimes due to collapsed hairs.

Megaspores, also called macrospores, are a type of spore that is present in heterosporous plants. These types of plants have two spore types, megaspores and microspores. Generally speaking, the megaspore, or large spore, germinates into a female gametophyte, which is fertilized by sperm produced...

: the larger of two kinds of spores produced by a heterosporous plant giving rise to the female gametophyte; compare microspore.
megastrobilus: the larger of two kinds of cones or strobili produced by gymnosperms, being female and producing the seeds; compare microstrobilus.
Biological membrane
A biological membrane or biomembrane is an enclosing or separatingmembrane that acts as a selective barrier, within or around a cell. It consists of a lipid bilayer with embedded proteins that may constitute close to 50% of membrane content...

: thin, translucent and flexible, seldom green.
  • mericarp: one segment of a fruit (a schizocarp) that splits at maturity into units derived from the individual carpels, or a carpel, usually 1-seeded, released by the break-up at maturity of a fruit formed from 2 or more joined carpels.

  • meristem
    A meristem is the tissue in most plants consisting of undifferentiated cells , found in zones of the plant where growth can take place....

    : a group of actively dividing tissues.

  • mesic
    Mesic habitat
    In ecology, a mesic habitat is a type of habitat with a moderate or well-balanced supply of moisture, e.g., a mesic forest, a temperate hardwood forest, or dry-mesic prairie. Compared to a dry habitat, a mesic habitat is moister....

    : moist, avoiding both extremes of drought and wet; pertaining to conditions of moderate moisture or water supply; applied to organisms (vegetation) occupying moist habitats.

  • mesocarp: the fleshy portion of the wall of a succulent fruit inside the skin and outside the stony layer (if any), surrounding the seed(s); sarcocarp.

  • mesomorphic: soft and with little fibrous tissue, but not succulent.

  • mesophyll: photosynthetic tissue of a leaf, the central tissues between the upper and lower epidermis; a medium-sized leaf, with area between 20 and 180 cm^2.

  • mesophyllous: (of vegetation) of moist habitats and having mostly large and soft leaves.

  • mesophyte
    Mesophytes are terrestrial plants which are adapted to neither a particularly dry nor particularly wet environment. An example of a mesophytic habitat would be a rural temperate meadow, which might contain Goldenrod, Clover, Oxeye Daisy, and Rosa multiflora.Mesophytes make up the largest ecological...

    : a plant thriving under intermediate environmental conditions of moderate moisture and temperature, without major seasonal fluctuations.

In biology, a microspore is a small spore as contrasted to the larger megaspore.In botany, microspores develop into male gametophytes, whereas megaspores develop into female gametophytes. The combination of megaspores and microspores is found only in heterosporous organisms...

: the smaller of two kinds of spores produced by a heterosporous plant; compare megaspore.
microstrobilus: the smaller of two kinds of cones or strobili produced by gymnosperms, being male and producing the pollen; compare megastrobilus.
midrib: the central, and usually most prominent, vein of a leaf or leaf-like organ; midvein.
midvein: see midrib.
  • moniliform: resembling a string of beads.

  • monochasium: a cymose inflorescence with the branches arising singly; cf. dichasium.

  • monocots: abbreviation of monocotyledons.

Monocotyledons, also known as monocots, are one of two major groups of flowering plants that are traditionally recognized, the other being dicotyledons, or dicots. Monocot seedlings typically have one cotyledon , in contrast to the two cotyledons typical of dicots...

: a flowering plant whose embryo has one cotyledon (seed leaf); compare dicotyledon.
  • monoecious: of vascular plants, where the male and female reproductive structures are in separate flowers but on the same plant; of inflorescence, including unisexual flowers of both sexes; cf. dioecious.

A monograph is a work of writing upon a single subject, usually by a single author.It is often a scholarly essay or learned treatise, and may be released in the manner of a book or journal article. It is by definition a single document that forms a complete text in itself...

: of a group of plants, a comprehensive treatise presenting an analysis and synthesis of taxonomic knowledge of that taxon; the fullest account possible (at the time) of a family, tribe or genus. It is generally worldwide in scope and evaluates all taxonomic treatments of that taxon including studies of its evolutionary relationships with other related taxa, and cytological, genetic, morphological, palaeobotanical and ecological studies. The term is often incorrectly applied to any systematic work devoted to a single taxon. Compare revision.
  • monotypic
    In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...

    : containing only one taxon of the next lower rank, e.g. a family with only one genus, or a genus that includes only a single species.

  • morphology
    Morphology (biology)
    In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....

    : the shape or form of an organism or part thereof.

  • mucro: a sharp, short point.

  • mucronate: terminating in a mucro.

  • multiple fruit
    Multiple fruit
    Multiple fruits are fruits that are formed from a cluster of flowers . Each flower in the inflorescence produces a fruit, but these mature into a single mass...

    : a cluster of fruits produced from more than one flower and appearing as a single fruit, often on a swollen axis, as in Moraceae; cf. aggregate fruit.

  • muricate: covered with short hard protuberances.

  • mutation
    In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...

    : an abrupt and inexplicable variation from the norm, such as the doubleness in flowers, changes in colour, or habit of growth.


  • native
    Indigenous (ecology)
    In biogeography, a species is defined as native to a given region or ecosystem if its presence in that region is the result of only natural processes, with no human intervention. Every natural organism has its own natural range of distribution in which it is regarded as native...

    : naturally occurring in an area, but not necessarily confined to it; cf. endemic.

  • natural hybrid: a hybrid taxon produced by chance in the wild.

  • naturalised
    Naturalisation (biology)
    In biology, naturalisation is any process by which a non-native organism spreads into the wild and its reproduction is sufficient to maintain its population. Such populations are said to be naturalised....

    : describing a plant, introduced from another region, that grows and reproduces readily in competition with the natural flora.

  • nectar: a (usually sweet) fluid produced by the flowers of many plants, collected by bees and other insects.

  • nectary (adjective nectariferous): a specialized gland that secretes nectar.

  • neophyte
    Neophyte (botany)
    In botany, a neophyte is a plant species which is non-native to a geographical region, and was introduced in recent history. Plants that are long-established in an area are called archaeophytes...

    : a plant that was recently introduced to a geographic area; cf. archaeophyte.

nerve: see vein.
  • New World
    New World
    The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...

    : the Americas.

node: the part of a stem where leaves or branches arise.
  • nomen conservandum: (Latin) a name which although, contrary to the rules of nomenclature (usually a later synonym), must be adopted.

  • nomen illegitimum
    Nomen illegitimum
    A nomen illegitimum is a technical term, used mainly in botany. It is usually abbreviated as nom. illeg..-Definition:...

    : (Latin) a name that is superfluous at its time of publication either because the taxon to which it was applied already has a name, or because the name has already been applied to another plant.

  • nomen invalidum: (Latin) a name that is not valid. It can also refer to a name that is not validly published. (Abbreviation: nom. inval.)

  • nomen nudum
    Nomen nudum
    The phrase nomen nudum is a Latin term, meaning "naked name", used in taxonomy...

    : (Latin) a name not published in accordance with the International Code of Botanical Nomenclature, usually without a diagnosis or description of the entity to which it applies, and without reference to either; such a name should not be used.

  • nomenclature
    Nomenclature is a term that applies to either a list of names or terms, or to the system of principles, procedures and terms related to naming - which is the assigning of a word or phrase to a particular object or property...

    : the naming of things; often restricted to the correct use of scientific names in taxonomy; a system that sets out provisions for the formation and use of names.

  • noxious: of plants, containing harmful or unwholesome qualities. Applied in conjunction with 'weed' to specifically describe a plant which legislation deems harmful to the environment. Each state and territory in Australia has specific legislation governing noxious weeds.

  • numerous: Stamens are described as numerous when there are more than twice as many as sepals or petals.

  • nut
    Nut (fruit)
    A nut is a hard-shelled fruit of some plants having an indehiscent seed. While a wide variety of dried seeds and fruits are called nuts in English, only a certain number of them are considered by biologists to be true nuts...

    : a hard, dry, indehiscent fruit, containing only one seed.

  • nutlet: a small nut, one of the lobes or sections of the mature ovary of some members of the Boraginaceae, Verbenaceae, and Lamiaceae.


  • ob-: inversely; usually same shape as suffix but attached by the narrower end, for example obcordate, oblanceolate, obovate.

  • obconic
    In botany, an obconic is an inverted cone shape. The term is most frequently applied to certain fruit or hypanthium structures with the apical end attached to the stem; however, less frequently the usage may apply to the pistil structure. In the case of fungi the designation is often made to the...

    : of a fruit, hypanthium, pistil or calyx structure; an inverted cone shape

obcordate: of a leaf blade, broad and notched at the tip; heart shaped but attached at the pointed end.
oblanceolate: a 2-dimensional shape, lanceolate but broadest in the upper third; cf. lanceolate.
Obligate parasite
An obligate parasite is a parasitic organism that cannot complete its life cycle without dependence on its host.-See also:*Obligate intracellular parasite*Parasitism*Parasitic plant*Facultative parasite...

: of parasites, unable to survive without the host; compare faculative.
  • oblique: slanting; of a leaf, larger on one side of the midrib than the other, in other words asymmetrical.

  • oblong: length a few times greater than width, with sides almost parallel and ends rounded.

obovate: of a leaf, a 2-dimensional shape of which the length is about 1.5 times the width, and widest above the centre.
obtuse: blunt or rounded at the tip or apex; converging edges making an angle of more than 90°; compare acute. See Leaf shape
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...

  • Oceania
    Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...

    : the islands of the Pacific (sometimes including Australia).

  • ocrea (ochrea): a sheath, formed from two stipules, encircling the node in Polygonaceae.

  • odd-pinnate: (imparipinnate) having an odd number of leaflets in a compound leaf.

  • Old World
    Old World
    The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....

    : the world known before the discovery of America; essentially Europe and Asia.

  • olim: formerly, e.g., "olim B", formerly in the Berlin herbarium
    In botany, a herbarium – sometimes known by the Anglicized term herbar – is a collection of preserved plant specimens. These specimens may be whole plants or plant parts: these will usually be in a dried form, mounted on a sheet, but depending upon the material may also be kept in...

     (Herbarium Berolinense).

  • ontogeny
    Ontogeny is the origin and the development of an organism – for example: from the fertilized egg to mature form. It covers in essence, the study of an organism's lifespan...

    : the sequence of developmental stages through which an organism passes.

  • operculum
    Operculum (botany)
    An operculum, in botany, is a term generally used to describe a structure within a plant, moss, or fungus acting as a cap, flap, or lid. In plants, it may also be called a bud cap.Examples of structures identified as opercula include:...

    (calyptra): a lid or cover that becomes detached at maturity, e.g. in Eucalyptus, a cap covering the bud and formed by the fusion or cohesion of perianth parts.

  • opposite: (as adjective) leaves or flowers borne at the same level but on opposite sides of the axis; or (as verb) when something occurs on the same radius as something else, for example anthers opposite sepals; compare alternate.

  • orbicular: flat and more or less circular.

  • order
    Order (biology)
    In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

    : a group of one or more families sharing common features, ancestry, or both.

  • ortet: the original single parent plant from which a clone ultimately derives.

  • orthotropous: when an ovule is erect, with the micropyle directed away from the placenta; atropous; cf. amphitropous, anatropous, campylotropous.

An oval is any curve resembling an egg or an ellipse, such as a Cassini oval. The term does not have a precise mathematical definition except in one area oval , but it may also refer to:* A sporting arena of oval shape** a cricket field...

: see elliptical.
Ovary (plants)
In the flowering plants, an ovary is a part of the female reproductive organ of the flower or gynoecium. Specifically, it is the part of the pistil which holds the ovule and is located above or below or at the point of connection with the base of the petals and sepals...

: the basal portion of a carpel or group of fused carpels, enclosing the ovule(s).
ovate: shaped like a section through the long-axis of an egg and attached by the wider end.
  • ovoid: egg-shaped, with wider portion at base; 3-dimensional object, ovate in all sections through long-axis.

Ovule means "small egg". In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: The integument forming its outer layer, the nucellus , and the megaspore-derived female gametophyte in its center...

: loosely, the seed before fertilization; a structure in a seed plant within which one or more megaspores are formed (after fertilization it develops into a seed).


  • palea
    Palea is a city in Equatorial Guinea. It is located in Annobón Province and has a population of 4433....

    : the upper of 2 bracts enclosing a grass flower.

  • palmate: (1) a compound leaf divided into several leaflets arising from the same point at the top of the petiole; (2) of veins in a simple leaf when they arise in a similar fashion.

  • palmatifid: deeply divided into several lobes arising from more or less the same level.

  • palmatisect: intermediate between palmate and palmatifid, i.e. the segments are not fully separated at the base; often more or less digitate.

  • panicle
    A panicle is a compound raceme, a loose, much-branched indeterminate inflorescence with pedicellate flowers attached along the secondary branches; in other words, a branched cluster of flowers in which the branches are racemes....

    (adjective paniculate): a compound raceme; an indeterminate inflorescence in which the flowers are borne on branches of the main axis or on further branches of these.

  • papilionate: butterfly-like; with a corolla like that of a pea.

  • papilla (plural papillae, adjective papillose): a small, elongated protuberance on the surface of an organ, usually an extension of one epidermal cell.

  • pappus
    Pappus (flower structure)
    The pappus is the modified calyx, the part of an individual disk, ray or ligule floret surrounding the base of the corolla, in flower heads of the plant family Asteraceae. The pappus may be composed of bristles , awns, scales, or may be absent. In some species, the pappus is too small to see...

    : in daisy florets, a tuft or ring of hairs or scales borne above the ovary and outside the corolla (representing the missing calyx); a tuft of hairs on a fruit.

parasite: an organism living on or in a different organism, from which it derives nourishment; compare saprophyte, epiphyte.
  • parietal: attached to the marginal walls of a structure, for example ovules attached to placentas on the wall of the ovary. See Placentation
    In biology, placentation refers to the formation, type and structure, or arrangement of placentas. The function of placentation is to transfer nutrients from maternal tissue to a growing embryo...


paripinnate: having an even number of leaflets (or pinnae), that is terminated by a pair of pinnae as opposed to a single pinna; compare imparipinnate.
  • patent: of plants, spreading.

  • pectinate: pinnately divided with narrow segments closely set like the teeth of a comb.

  • pedate
    Pedate is a term used in biology to describe certain structures resembling feet, or the quality of having feet. It derives from the Latin verb "pedo", meaning "to furnish with feet".-Plants:...

    : with a terminal lobe or leaflet, and on either side of it an axis curving outwards and backwards, bearing lobe or leaflets on the outer side of the curve.

  • pedicel
    Pedicel (botany)
    A pedicel is a stem that attaches single flowers to the main stem of the inflorescence. It is the branches or stalks that hold each flower in an inflorescence that contains more than one flower....

    (adjective pedicellate): the stalk of a flower.

  • peduncle
    Peduncle (botany)
    In botany, a peduncle is a stem supporting an inflorescence, or after fecundation, an infructescence.The peduncle is a stem, usually green and without leaves, though sometimes colored or supporting small leaves...

    (adjective pedunculate): the stalk of an inflorescence.

  • peltate: shield-like; with stalk attached to the lower surface and not to the margin.

  • pellucid: transmitting light; for example, said of tiny dots in leaves visible when held in front of light.

pendulous: hanging, for example an ovule attached to a placenta on the top of the ovary; compare suspended.
  • penicillate: tufted like an artist's brush; with long hairs towards one end.

  • penninervation (penninerved): with pinnately arranged veins.

  • pepo: type of berry formed from an inferior ovary and containing many seeds, usually large with a tough outer skin, for instance, pumpkin
    A pumpkin is a gourd-like squash of the genus Cucurbita and the family Cucurbitaceae . It commonly refers to cultivars of any one of the species Cucurbita pepo, Cucurbita mixta, Cucurbita maxima, and Cucurbita moschata, and is native to North America...

    , cucumber
    The cucumber is a widely cultivated plant in the gourd family Cucurbitaceae, which includes squash, and in the same genus as the muskmelon. The plant is a creeping vine which bears cylindrical edible fruit when ripe. There are three main varieties of cucumber: "slicing", "pickling", and...


  • perennating: of an organ that survives vegetatively from season to season. A period of reduced activity between seasons is usual.

  • perennial: a plant whose life span extends over several years.

  • perfect: of a flower, when bisexual.

  • perfoliate: with its base wrapped around the stem (so that the stem appears to pass through it), e.g. of leaves and bracts.

  • perianth
    The term perianth has two similar but separate meanings in botany:* In flowering plants, the perianth are the outer, sterile whorls of a flower...

    : the collective terms for the calyx and corolla of a flower (generally used when the two are similar).

  • pericarp: the wall of a fruit, developed from the ovary wall.

  • perigynous: borne around the ovary, i.e. of perianth segments and stamens arising from a cup-like or tubular extension of receptacle (free from the ovary but extending above its base); cf. epigynous, hypogynous.

persistent: remaining attached to the plant beyond the usual time of falling, for instance sepals not falling after flowering, flower parts remaining through maturity of fruit; compare deciduous, caducous.
  • perule: (1) the scaly covering of a leaf or flower bud; (2) in camellias the final bracts and sepals become indistinguishable and are called perules; (3) a kind of sac formed by the adherent bases of the two lateral sepals in certain orchids.

Petals are modified leaves that surround the reproductive parts of flowers. They often are brightly colored or unusually shaped to attract pollinators. Together, all of the petals of a flower are called a corolla. Petals are usually accompanied by another set of special leaves called sepals lying...

: in a flower, one of the segments or divisions of the inner whorl of non-fertile parts surrounding the fertile organs, usually soft and conspicuously coloured; compare sepal.
  • petaloid: like a petal; soft in texture and coloured conspicuously.

  • petiolate: subtended by a petiole.

  • petiole
    Petiole (botany)
    In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...

    : the stalk of a leaf.

  • petiolule: the stalk of a leaflet.

  • phanerogam: gymnosperms and angiosperms; plants producing stamens and gynoecia; literally plants with conspicuous sexual reproductive organs; cf. cryptogams.

  • photosynthesis
    Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...

    : the process by which sugars are made from carbon dioxide and water in cells containing chloroplasts; the chemical energy required from solar energy in the presence of the pigment chlorophyll.

  • phyllode (adjective phyllodineous): a leaf with the blade much reduced or absent, and in which the petiole and or rachis perform the functions of the whole leaf; e.g. many acacias; cf. cladode.

  • phytomelan a black, inert, carbonaceous material that lacks nitrogen, probably derived from catechol, that forms a crust-like covering of some seeds, commonly found in Asparagales, Asteraceae, etc.

  • pilose: covered with soft, weak, thin and clearly separated hairs, which are usually defined as long and sometimes ascending.

pinna (plural pinnae): a primary segment of a compound leaf.
Pinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...

: a compound leaf with leaflets arranged on each side of a common petiole or axis; also applied to how the lateral veins are arranged in relation to the main vein.
  • pinnatifid: pinnately lobed.

  • pinnatisect: pinnately divided almost to midrib but segments still confluent.

  • pinnule: ultimate free division (or leaflet) of a compound leaf.

  • pistil: (1) a single carpel when the carpels are free; (2) a group of carpels when the carpels are united by the fusion of their walls.

  • pith
    Pith, or medulla, is a tissue in the stems of vascular plants. Pith is composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant. In eudicots, pith is located in the center of the stem. In monocots, it extends also into flowering stems and roots...

    : the central region of a stem, inside the vascular cylinder; the spongy parenchymatous central tissue in some stems and roots.

In biology, placentation refers to the formation, type and structure, or arrangement of placentas. The function of placentation is to transfer nutrients from maternal tissue to a growing embryo...

: the tissue within an ovary to which the ovules are attached.
  • placentation
    In biology, placentation refers to the formation, type and structure, or arrangement of placentas. The function of placentation is to transfer nutrients from maternal tissue to a growing embryo...

    : the arrangement of ovules inside ovary; for example axile, free-central, parietal, marginal, basal, or apical.

  • Plant Breeders Rights (PBR): these rights, governed by Plant Breeder's Rights Acts give the plant breeder legal protection over the propagation of a cultivar, and the exclusive rights to produce and to sell it, including the right to license others to produce and sell plants and reproductive material of a registered, deliberately bred variety. Cf. UPOV.

  • Plant Variety Rights (PVR): governed by the Plant Variety Rights the registration of new varieties is now governed by Plant Breeders Rights.

  • Plastochron: the time between successive leaf initiation events.

  • plicate: pleated; folded back and forth longitudinally like a fan.

  • -plinerved: (of leaves) a suffix indicating that the main nerves are lateral and arise from a point distinctly above the base of the leaf. Combined with a numerical prefix to form words like 3-plinerved, 5-plinerved, and so on. Such leaves are especially characteristic of the family Melastomataceae.

  • plumose: like a feather; with fine hairs branching from a main axis.

  • plumule: the part of an embryo that gives rise to the shoot system of a plant; cf. radicle.

  • pneumatophore: a vertical, aerial (at low tide) appendage to the roots of some plants, through which gases are exchanged; e.g. on mangroves.

  • pod: (1) a legume, the fruit of a leguminous plant, a dry fruit of a single carpel, splitting along two sutures; (2) siliqua and silicula, the fruit of Brassicaceae
    Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....

    , a dry fruit composed of two carpels separated by a partition.

  • pollen
    Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...

    : powdery mass shed from anthers (of angiosperms) or microsporangia (of gymnosperms); the microspores of seed plants; pollen-grains.

  • pollen-mass: pollen-grains cohering by a waxy texture or fine threads into a single body; pollinium; e.g. in orchids.

  • pollination
    Pollination is the process by which pollen is transferred in plants, thereby enabling fertilisation and sexual reproduction. Pollen grains transport the male gametes to where the female gamete are contained within the carpel; in gymnosperms the pollen is directly applied to the ovule itself...

    : the transfer of pollen from the male organ (anther) to the receptive region of a female organ (stigma).

  • pollinium
    Pollinium, or plural pollinia, is a coherent mass of pollen grains in a plant.They are the product of only one anther, but are transferred, during pollination, as a single unit. This is regularly seen in plants such as orchids and many species of milkweeds .Most orchids have waxy pollinia...

    : see pollen-mass.

  • polygamodioecious: having bisexual and male flowers on some plants and bisexual and female flowers on others; cf. androdioecious, andromonoecious, dioecious, monoecious, polygamomonoecious, polygamous.

  • polygamomonoecious
    The term polygamomonoecious has two meanings in botany:*an individual plant with male, female, and perfect flowers on the same plant, called trimonoecious or polygamomonoecious plants;...

    : having male, female and bisexual flowers on the same plant; cf. androdioecious, andromonoecious, polygamodioecious, polygamous.

  • polygamous: having bisexual and unisexual flowers on the same plant.

  • polymorphic: of several different kinds (in respect to shape and/or size).

  • polyploid: with more than two of the basic sets of chromosomes in the nucleus; any individual (or a cell) containing three or more complete sets of chromosomes. Various combinations of words or numbers with '-ploid' indicate the number of haploid sets of chromosomes; e.g. triploid = 3 sets, tetraploid = 4 sets, pentaploid = 5 sets, hexaploid = 6 sets, and so on.

  • pome
    In botany, a pome is a type of fruit produced by flowering plants in the subfamily Maloideae of the family Rosaceae.A pome is an accessory fruit composed of one or more carpels surrounded by accessory tissue...

    : a fruit that has developed partly from the ovary wall but mostly from the floral tube, e.g., apple.

  • population
    A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...

    : (1) all individuals of one or more species within a prescribed area; (2) a group of organisms of one species, occupying a defined area and usually isolated to some degree from other similar groups; (3) in statistics, the whole group of items or individuals under investigation.

posterior: the side nearest the axis; compare anterior.
  • prickle (adjective: prickly): hard, pointed outgrowth from the surface of a plant (involving several layers of cells but not containing a vein); sharp outgrowth from the bark, detachable without tearing wood; cf. thorn.

  • prophyll: a leaf formed at the base of a shoot, usually smaller than those formed later.

  • pro parte: (Latin) in part; in nomenclature, to denote that the preceding taxon includes more than one currently recognized entity, and that only one of those entities is being considered.

  • procumbent: spreading along the ground but not rooting at the nodes: not as close to ground as prostrate.

  • propagules: a structure capable of producing a new plant; includes seeds, spores, bulbils, etc.

  • prostrate: lying flat on the ground.

  • protandrous: male sex organs maturing before the female ones, e.g. a flower shedding pollen before the stigma is receptive; cf. protogynous.

  • prothallus: a gametophyte body, usually flattened and delicate; e.g. in ferns and fern allies.

  • protogynous: female sex organs maturing before the male ones, e.g. a flower shedding pollen after the stigma has ceased to be receptive; cf. protandrous.

  • proximal: near the point of origin or attachment; cf. distal.

  • pruinose: covered with a powdery, waxy material; with a bloom.

  • pseudo
    The prefix pseudo- is used to mark something as false, fraudulent, or pretending to be something it is not.-See also:*Falsehood*Pseudorealism*Deception*Mimicry**Pseudo: Blood of Our Own...

    : false; apparently but not genuine; e.g. pseudo-bulb = a thickened, bulb-like internode in orchids, or a corm.

  • puberulous (puberulent): covered with minute soft erect hairs.

  • pubescent: downy; covered with short, soft, erect hairs.

  • pulvinus
    A pulvinus is a joint-like thickening at the base of a plant leaf or leaflet that facilitates growth-independent movement. It consists of a core of vascular tissue within a flexible, bulky cylinder of thin-walled parenchyma cells...

    : a swelling at the base of a leaf or leaflet stalk, often glandular or responsive to touch.

  • punctate: marked with dots.

  • pungent: having a sharp hard point.

  • pyramidal: of a plant's form, tetrahedral, pyramid-shaped.

  • pyrene
    Pyrene is a polycyclic aromatic hydrocarbon consisting of four fused benzene rings, resulting in a flat aromatic system. The chemical formula is . This colourless solid is the smallest peri-fused PAH...

    : the stone of a drupe, consisting of the seed surrounded by the hardened endocarp.

  • pyriform: pear
    The pear is any of several tree species of genus Pyrus and also the name of the pomaceous fruit of these trees. Several species of pear are valued by humans for their edible fruit, but the fruit of other species is small, hard, and astringent....



  • raceme
    A raceme is a type of inflorescence that is unbranched and indeterminate and bears pedicellate flowers — flowers having short floral stalks called pedicels — along the axis. In botany, axis means a shoot, in this case one bearing the flowers. In a raceme, the oldest flowers are borne...

    (adjective racemose): an indeterminate inflorescence in which the main axis produces a series of flowers on lateral stalks, the oldest at the base and the youngest at the top; cf. spike.

  • rachilla (rhachilla): the axis of a grass spikelet, above the glumes.

Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...

(plural rachises; rachides): the axis of an inflorescence or a pinnate leaf; for example ferns; secondary rachis is the axis of a pinna in a bipinnate leaf distal to and including the lowermost pedicel attachment
  • radial: with structures radiating from a central point as spoke
    A spoke is one of some number of rods radiating from the center of a wheel , connecting the hub with the round traction surface....

    s on a wheel, for example, the lateral spines of a cactus.

radiate: of daisies, of a capitulum, with ray florets surrounding disc florets.
  • radical: springing from the root; clustered at base of stem.

  • radicle
    In botany, the radicle is the first part of a seedling to emerge from the seed during the process of germination. The radicle is the embryonic root of the plant, and grows downward in the soil...

    : the part of an embryo giving rise to the root system of a plant; cf. plumule.

  • rainforest
    Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...

    : a forest dominated by broad-leaved trees with dense crowns that form a continuous layer (canopy) and with one or more of the following growth forms: epiphytes, lianas, treeferns, palms; eucalypts absent or are present only as isolated emergen, e.g. in Victoria, mesic vegetation is dominated by trees other than eucalypts, often with lianas and epiphytes.

  • ramet
    Râmeţ is a commune located in Alba County, Romania. It has a population of 751, and is composed of thirteen villages: Boţani, Brădeşti, Cheia, Cotorăşti, Floreşti, Olteni, Râmeţ, Valea Făgetului, Valea Inzelului, Valea Mănăstirii, Valea Poienii, Valea Uzei and Vlădeşti.-References:...

    : an individual member of a clone.

ray: (1) zygomorphic (ligulate) flowers in a radiate flowerhead, that is, ray-florets/flowers, for example Asteraceae
The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

; (2) each of the branches of an umbel.
  • receptacle: the axis of a flower, in other words, floral axis; torus; for example in Asteraceae
    The Asteraceae or Compositae , is an exceedingly large and widespread family of vascular plants. The group has more than 22,750 currently accepted species, spread across 1620 genera and 12 subfamilies...

    , the floral base or common receptacle is the expanded summit of the peduncle on which the flowers are inserted.

  • recurved: bent or curved backwards or downwards.

  • reflexed: bent sharply back or down.

  • registered name: a cultivar name accepted by the relevant International Cultivar Registration Authority
    International Cultivar Registration Authority
    An International Cultivation Registration Authority is an organization responsible for ensuring that each plant cultivar receives a unique, authoritative botanical name....


registered trade mark: a trade mark formally accepted by a statutory trade-mark authority and distinguished by the international ® sign.
  • registration: (1) the act of recording a new cultivar name with an International Cultivar Registration Authority
    International Cultivar Registration Authority
    An International Cultivation Registration Authority is an organization responsible for ensuring that each plant cultivar receives a unique, authoritative botanical name....

    ; (2) recording a new cultivar name with a statutory authority like the Plant Breeder’s Rights Office (3) recording a trade mark with a trade marks office. Compare registered trade mark.

regular: see actinomorphic.
  • reniform: kidney-shaped.

  • reticulate: forming a network (or reticulum), e.g. veins that join one another at more than one point.

  • retrorse: directed backwards or downwards; cf. antrorse.

  • retuse: with a blunt (obtuse) and slightly notched apex.

revision: an account of a particular plant group, like an abbreviated or simplified monograph. Sometimes confined to the plants of a particular region. Similar to a monograph in clearly distinguishing the taxa and providing a means for their identification; compare monograph.
revolute: rolled under (downwards or backwards), for example when the edges of leaves are rolled under towards the midrib; compare involute.
  • rhachis: see rachis.

In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...

: a perennial underground stem usually growing horizontally. See also stolon.
rhombic: like a rhombus
In Euclidean geometry, a rhombus or rhomb is a convex quadrilateral whose four sides all have the same length. The rhombus is often called a diamond, after the diamonds suit in playing cards, or a lozenge, though the latter sometimes refers specifically to a rhombus with a 45° angle.Every...

: an oblique figure with four equal sides; compare trapeziform, trullate.
  • rhomboid
    Traditionally, in two-dimensional geometry, a rhomboid is a parallelogram in which adjacent sides are of unequal lengths and angles are oblique.A parallelogram with sides of equal length is a rhombus but not a rhomboid....

    : a four-sided figure with opposite sides parallel but with adjacent sides an unequal length (like an oblique rectangle); see also rhombic.

  • rhomboidal: a shape, for instance of a leaf, that is roughly diamond-shaped with length equal to width.

  • root
    In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

    : a unit of a plant's axial system which is usually underground, does not bear leaves, tends to grow downwards, and is typically derived from the radicle of the embryo.

  • root hairs: outgrowths of the outermost layer of cells just behind the root tips, functioning as water-absorbing organs.

A rootstock is a plant, and sometimes just the stump, which already has an established, healthy root system, used for grafting a cutting or budding from another plant. The tree part being grafted onto the rootstock is usually called the scion...

: short, erect, swollen structure at junction of a plant's root and shoot systems, for example a corm. Also used to describe (1) a part of a budded or grafted plant which supplies the roots, also called a rootstock, or plants grown specifically to produce these; (2) plants or seeds with some specific attribute, for instance virus-free plants.
  • rosette
    Rosette (botany)
    In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...

    : when parts are not whorled or opposite but appear so, due to the contractions of internodes, e.g. the petals in a double rose or a basal cluster of leaves (usually close to the ground) in some plants.

  • rostrate
    Rostrum (anatomy)
    The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....

    : with a beak.

  • rotate: circular and flattened; for example a corolla with a very short tube and spreading lobes (for instance some Solanaceae
    Solanaceae are a family of flowering plants that include a number of important agricultural crops as well as many toxic plants. The name of the family comes from the Latin Solanum "the nightshade plant", but the further etymology of that word is unclear...


rudimentary: poorly developed and not functional; compare vestigial.
  • rugose: wrinkled.

  • rugulose: finely wrinkled.

  • runcinate: sharply pinnatifid or cleft, the segments directed downward.

  • runners: see stolon.

  • rupicolous: rupestral, saxicolous, growing on or among rocks. (compare lithophytic)

  • rush: a plant belonging to the family Juncaceae
    Juncaceae, the rush family, are a monocotyledonous family of flowering plants. There are eight genera and about 400 species. Members of the Juncaceae are slow-growing, rhizomatous, herbaceous plants, and they may superficially resemble grasses. They often grow on infertile soils in a wide range...

     or, more loosely, applied to various monocotyledons.


  • saccate: pouched.

  • sagittate: shaped like the head of an arrow; narrow and pointed but gradually enlarged at base into two straight lobes directed downwards; may refer only to the base of a leaf with such lobes; cf. hastate.

  • samara
    Samara (fruit)
    A samara is a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit and indehiscent . It is a winged achene...

    : a dry, indehiscent fruit with its wall expanded into a wing.

  • samphire
    Samphire is a name given to a number of very different edible plants that happen to grow in coastal areas.*Rock samphire, Crithmum maritimum is a coastal species with white flowers that grows in the United Kingdom...

    : (in Australia) any plant of the tribe Salicorniae (chenopodiaceae), e.g. Sarcocornia, Halosarcia, Sclerostegia; or a community dominated by one or more of these species.

saprophyte (adjective saprophytic): an organism deriving its nourishment from decaying organic matter and usually lacking chlorophyll; compare parasite, epiphyte.
  • scabrid (scabrous): rough to the touch with short hard emergences or hairs.

  • scale: (1) a reduced or rudimentary leaf, for example around a dormant bud; (2) a flattened epidermal outgrowth, such as those commonly found on the leaves and rhizomes of ferns.

  • scandent
    A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...

    : climbing, by whatever means. See also: scandent in Wiktionary.

  • scape
    Scape (botany)
    In botany, scapes are leafless flowering stems that rise from the ground. Scapes can have a single flower or many flowers, depending on the species....

    (adjective scapose): a stem-like flowering stalk of a plant with radical leaves.

  • scapose: having the floral axis more or less erect with a few leaves or devoid of leaves; consisting of a scape
    In biology, the term scape may refer to:* The first segment of an insect antenna* A finger-like appendage of the epigyne of a female spider* Scape , a flowering stemScape may also refer to:...


  • scarious: dry and membranous.

  • schizocarp
    A schizocarp is a dry fruit that develops from multiple carpels. When mature it splits up into mericarps. Mericarps are often 1-seeded as in, for example, Malva, Malvastrum, and Sida...

    : a dry fruit formed from more than one carpel but breaking apart into individual carpels (mericarps) when ripe.

  • scion: the aerial part of a graft combination, induced by various means to unite with a compatible understock/roostock.

  • sclereid: a cell with a thick, often lignified, cell wall that is shorter than a fiber cell and dies soon after the thickening of its cell wall.

  • sclerenchyma: a strengthening or support tissue composed of sclereids or of a mixture of sclereids and fibers.

  • sclerophyll
    Sclerophyll is the term for a type of vegetation that has hard leaves and short internodes . The word comes from the Greek sclero and phyllon ....

    (adjective sclerophyllous): a plant with hard, stiff leaves; leaves stiffened with thick-walled cells.

  • scorpioid: of a cymose inflorescence, when it branches alternately on one side and then the other; cf. helicoid.

  • scrubland: dense vegetation dominated by shrubs.

  • section
    Section (botany)
    In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...

    (sectio): the category of supplementary taxa intermediate in rank between subgenus and series. It is a singular noun always written with a capital initial letter, in combination with the generic name.

  • secund
    Secund can refer to:*a botanical term used of plants when similar parts are directed to one side only, as flowers on an axis. *to loan an employee from one organization to another...

    : with all the parts grouped on one side or turned to one side (applied especially to inflorescences).

  • sedge: a plant belonging to the family Cyperaceae
    Cyperaceae are a family of monocotyledonous graminoid flowering plants known as sedges, which superficially resemble grasses or rushes. The family is large, with some 5,500 species described in about 109 genera. These species are widely distributed, with the centers of diversity for the group...


  • seed
    A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...

    : a ripened ovule, consisting of a protective coat enclosing an embryo and food reserves; a propagating organ formed in the sexual reproductive cycle of gymnosperms and angiosperms (together, the seed plants).

  • segment: part or subdivision of an organ, for example a petal is a segment of the corolla. A term sometimes used when the sepals and petals are indistinguishable.

  • self-pollination
    Self-pollination is a form of pollination that can occur when a flower has both stamen and a carpel in which the cultivar or species is self fertile and the stamens and the sticky stigma of the carpel contact each other in order to accomplish pollination...

    : also called selfing, the acceptance by stigmas of pollen from the same flower or from flowers on the same plant, which means they are self-compatible.

  • sensu
    Sensu is a Latin word meaning "in the sense of".It is used in a number of fields including biology, geology, linguistics, and law. Commonly it refers to how strictly or loosely an expression is used, but it also appears in expressions that indicate the convention or context of the usage.-Sensu and...

    : in the sense of.

  • sensu lato: of a plant name, in its broadest sense.

  • sensu stricto: of a plant name, in its narrowest sense.

A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...

: in a flower, one of the segments or divisions of the outer whorl of non-fertile parts surrounding the fertile organs, usually green; compare petal.
  • septicidal: of a fruit, when it dehisces along the partitions between loculi; cf loculicidal.

  • septum (plural septa): a partition, for example the membranous wall separating the two valves of the pod of Brassicaceae
    Brassicaceae, a medium sized and economically important family of flowering plants , are informally known as the mustards, mustard flowers, the crucifers or the cabbage family....


  • sericeous: silky with dense appressed hairs.

  • series
    Series (botany)
    Series is a low-level taxonomic rank below that of section but above that of species.In botany, a series is a subdivision of a genus...

    : the category of supplementary taxa intermediate in rank between section and species. It is a plural adjective; for instance Primula subgenus Primula sect. Primula series Acaules.

serrate: toothed with asymmetrical teeth pointing forward; like the cutting edge of a saw.
  • serrulate: finely serrate.

  • sessile
    Sessility (botany)
    In botany, sessility is a characteristic of plants whose flowers or leaves are borne directly from the stem or peduncle, and thus lack a petiole or pedicel...

    : without a stalk, e.g. of a stigma, when the style is absent.

  • seta
    Seta is a biological term derived from the Latin word for "bristle". It refers to a number of different bristle- or hair-like structures on living organisms.-Animal setae:In zoology, most "setae" occur in invertebrates....

    (adjectives setose, setaceous): a bristle or stiff hair (in Bryophytes, the stalk of the sporophyte); a terminal seta is an appendage to the tip of an organ, e.g. the primary rachis of a bipinnate leaf in Acacia.

  • sheath: a tubular or rolled part of an organ, e.g. the lower part of the leaf in most grasses.

  • shoot
    Shoots are new plant growth, they can include stems, flowering stems with flower buds, and leaves. The new growth from seed germination that grows upward is a shoot where leaves will develop...

    : usually the aerial part of a plant; a stem including its dependent parts, leaves flowers etc.

  • shrub
    A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

    : a woody perennial plant without a single main trunk, branching freely, and smaller than a tree.

  • sigmoid: shaped like the letter 'S'.

silicula: a stout siliqua (not more than twice as long as wide).
siliqua: a dry, dehiscent fruit (more than twice as long as wide) formed from a superior ovary of two carpels, with two parietal placentas and divided into two loculi by a 'false' septum.
  • silk
    Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...

    : densely covered with fine soft straight appressed hairs, with a lustrous sheen and satiny to the touch.

  • silviculture
    Silviculture is the practice of controlling the establishment, growth, composition, health, and quality of forests to meet diverse needs and values. The name comes from the Latin silvi- + culture...

    : the science of forestry and the cultivation of woodlands for commercial purposes and wildlife conservation.

  • simple: undivided, for instance a leaf not divided into leaflets (note, however, that a simple leaf may be entire, toothed or lobed) or an unbranched hair or inflorescence.

sinuate: with deep, wave-like depressions along the margins, but more or less flat; compare undulate.
  • sinus
    Sinus (botany)
    In botany, a sinus is a space or indentation, usually on a leaf, between two lobes or teeth that does not break the continuity of the structure....

    : a notch or depression between two lobes or teeth in the margin of an organ.

  • solitary: single, of flowers that grow one plant per year, one in each axil, or widely separated on the plant; not grouped in an inflorescence.

  • spadix
    In botany, a spadix is a type of spike inflorescence having small flowers borne on a fleshy stem. Spadix are typical of the Family Araceae known as arums or aroids...

    : a spicate inflorescence with a stout, often succulent axis.

  • spathe: a large bract ensheathing an inflorescence.

  • spathulate (spatulate): spoon-shaped; broad at the tip with a narrowed projection extending to the base.

  • species
    In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

    : a group, or populations of individuals, sharing common features and/or ancestry, generally the smallest group that can be readily and consistently recognized; often, a group of individuals capable of interbreeding and producing fertile offspring. The basic unit of classification, the category of taxa of the lowest principal rank in the nomenclatural hierarchy.

  • specific epithet: follows the name of the genus, and is the second word of a botanical binomial. The generic name and specific epithet together constitute the name of a species; i.e. the specific epithet is not the species name.

  • spike (adjective spicate): an unbranched, indeterminate inflorescence in which the flowers are without stalks; cf. raceme.

  • spikelet: a unit of the inflorescence especially in grasses, sedges and some other monocotyledons, consisting of one to many flowers and associated bracts (glumes).

  • spine (adjective spinose): a stiff, sharp structure, formed by the modification of a plant organ that contains vascular tissue; e.g. a lateral branch or a stipule; includes thorns.

  • spinescent: ending in a spine; modified to form a spine.

  • spiral
    In mathematics, a spiral is a curve which emanates from a central point, getting progressively farther away as it revolves around the point.-Spiral or helix:...

    : of arrangement, when plant parts are arranged in a succession of curves like the thread of a screw, or coiled in a cylindrical or conical manner.

  • sporangium
    A sporangium is an enclosure in which spores are formed. It can be composed of a single cell or can be multicellular. All plants, fungi, and many other lineages form sporangia at some point in their life cycle...

    (sporangia): a structure in which spores are formed.

  • spore
    In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

    : in non-flowering plants only a simple propagule, produced either sexually or asexually, and consisting of one or a few cells.

  • sporocarp
    Sporocarp (fungi)
    In fungi, the sporocarp is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne...

    : a fruiting body containing spores.

  • sporophyte
    All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...

    : a plant, or phase of a life cycle, that bears the spores; cf. gametophyte.

  • sport
    Bud sport
    A bud sport is a part of a plant or tree, for example, a leaf, shoot or flower, which due to a genetic mutation clearly differs from the rest of the plant, and which can also be grafted to grow new plants which retain this genetic difference as a new cultivar....

    : a naturally occurring variant of a species, not usually present in a population or group of plants; a plant that has spontaneously mutated so that it differs from its parent plant.

  • spreading: extending horizontally, for example branches; standing out at right angles to axis, for example leaves or hairs.

  • spur: (1) a short shoot; (2) a conical or tubular outgrowth from the base of a perianth segment, often containing nectar.

Plant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...

: the supporting structure of an organ, usually narrower in diameter than the organ.
The stamen is the pollen producing reproductive organ of a flower...

(adjective staminate): male organ of a flower, consisting (usually) of a stalk (filament) and a pollen-bearing portion (anther).
  • staminode
    In botany, a staminode is an often rudimentary, sterile or abortive stamen. This means that it does not produce pollen. Staminodes are frequently inconspicuous and stamen-like, usually occurring at the inner whorl of the flower, but are also sometimes long enough to protrude from the...

    : a sterile stamen, often rudimentary.

  • standard: the large posterior petal of pea-flowers.

  • standard specimen: a representative specimen of a cultivar (or other taxon), one that demonstrates how the name of that taxon should be used.

  • stellate: star-shaped, for example a type of hair.

Plant stem
A stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence , conifer cones, roots, other stems etc. The internodes distance one node from another...

: the plant axis, either aerial or subterranean, which bears nodes, leaves, branches and flowers.
  • stem-clasping: see amplexicaul.

  • sterile
    Sterility (physiology)
    Sterility is the physiological inability to effect sexual reproduction in a living thing, members of whose kind have been produced sexually. The term may be used in reference to* types of organism, such as the mule, a sterile hybrid;...

    : infertile, for example a stamen that does not bear pollen, or a flower that does not bear seed.

Stigma (botany)
The stigma is the receptive tip of a carpel, or of several fused carpels, in the gynoecium of a flower. The stigma receives pollen at pollination and it is on the stigma that the pollen grain germinates. The stigma is adapted to catch and trap pollen with various hairs, flaps, or sculpturings...

: the pollen-receptive surface of a carpel or group of fused carpels, usually sticky; usually a point or small head at the summit of the style.
Stipe (botany)
In botany, a stipe is a stalk that supports some other structure. The precise meaning is different depending on which taxonomic group is being described....

: in ferns, the stalk of a frond; generally a small stalk.
  • stipella (stipel; plural stipellae): one of two small secondary stipules at the base of leaflets in some species.

  • stipitate: stalked; borne on a stipe; of an ovary, borne on a gynophore

  • stipulate: bearing stipules.

In botany, stipule is a term coined by Linnaeus which refers to outgrowths borne on either side of the base of a leafstalk...

: small appendage at the bases of leaves in many dicotyledons.
In biology, stolons are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external skeletons.-In botany:...

: slender, prostrate or trailing stem, producing roots and sometimes erect shoots at its nodes. See also rhizome.
  • stoloniferous: having stolons.

  • stoma
    In botany, a stoma is a pore, found in the leaf and stem epidermis that is used forgas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the opening...

    (plural stomata): a pore; small hole in the surface of a leaf (or other aerial organ) allowing the exchange of gases between tissues and the atmosphere.

  • striate: striped with parallel, longitudinal lines or ridges.

  • strigose: covered with appressed, rigid, bristle-like, straight hairs; the appressed equivalent of hispid.

A strobilus is a structure present on many land plant species consisting of sporangia-bearing structures densely aggregated along a stem. Strobili are often called cones, but many botanists restrict the use of the term cone to the woody seed strobili of conifers...

(plural strobili): a cone-like structure consisting of sporophylls borne close together on an axis, for instance in some club-mosses, and other conifers.
Gynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...

: an elongated part of a carpel, or group of fused carpels, between the ovary and the stigma.
  • stylodium: an elongate stigma that resembles a style, a false style, e.g. commonly found in Poaceae and Asteraceae.

  • stylulus: the elongated apex of a free carpel which functions like the style of a syncarpous ovary, allowing pollen tubes from its stigma to enter the locule of only that carpel.

  • subgenus
    In biology, a subgenus is a taxonomic rank directly below genus.In zoology, a subgeneric name can be used independently or included in a species name, in parentheses, placed between the generic name and the specific epithet: e.g. the Tiger Cowry of the Indo-Pacific, Cypraea tigris Linnaeus, which...

    : the category of supplementary taxa intermediate between genus and section. It is a singular noun, always has a capital initial letter and is used in combination with the generic name; e.g. Primula subgenus Primula.

  • subshrub
    A subshrub or dwarf shrub is a short woody plant. Prostrate shrub is a similar term.It is distinguished from a shrub by its ground-hugging stems and lower height, with overwintering perennial woody growth typically less than 10–20 cm tall, or by being only weakly woody and/or persisting...

    : undershrub; small shrub which may have partially herbaceous stems, but generally a woody plant less than 1 m high.

  • subspecies
    Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

    : a grouping within a species, usually used for geographically isolated and morphologically distinct entities. Its taxonomic rank occurs between species and variety.

  • subtend: to stand beneath or close to, as in a bract at the base of a flower.

  • subulate: narrow and tapering gradually to a fine point.

  • succulent: juicy, fleshy; a plant with a fleshy habit.

Basal shoot
A basal shoot, root sprout, adventitious shoot, water sprout or sucker is a shoot or cane which grows from a bud at the base of a tree or shrub or from its roots. This shoot then becomes, or takes the form of, a singular plant. A plant that produces suckers is referred to as surculose...

: a shoot of more or less subterranean origin; an erect shoot originating from a bud on a root or a rhizome, sometimes at some distance from the stem of the plant.
  • sulcate: furrowed; grooved.

  • superficial
    Superficial may refer to:*Superficial , an album by Heidi Montag*"Superficial" *The Superficial, a website devoted to celebrity gossip...

    : on the surface
    In mathematics, specifically in topology, a surface is a two-dimensional topological manifold. The most familiar examples are those that arise as the boundaries of solid objects in ordinary three-dimensional Euclidean space R3 — for example, the surface of a ball...


superior: of an ovary, borne above the level of attachment of the other floral parts, or above the base of a floral tube (that is, one that is free from the ovary and bears the perianth and stamens); compare inferior, half-inferior.
suspended: of an ovule, when attached slightly below the summit of the ovary; compare pendulous.
  • suture: a junction or seam of union. (see fissure, commissure)

sward: extensive, more or less even cover of a surface, for example a lawn grass; compare tussock.
  • sympatric: with more or less similar or overlapping ranges of distribution.

  • syn- (sym-): with, together.

  • synangium: a fused aggregate of sporangia.

  • syncarpous: of a gynoecium, made up of united carpels.

  • synonym
    Synonym (taxonomy)
    In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...

    : outdated name or 'alternative' name for the same taxon.


  • taproot
    A taproot is an enlarged, somewhat straight to tapering plant root that grows vertically downward. It forms a center from which other roots sprout laterally.Plants with taproots are difficult to transplant...

    : the main, descending root of a plant with a single dominant root axis.

|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...

(plural taxa): a group or category in a system of classification, derived from the Greek prefixes taxo-, taxis- meaning arrangement.
  • taxonomy
    Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

    : the study of the principles and practice of classification.

  • tendril
    In botany, a tendril is a specialized stem, leaf or petiole with a threadlike shape that is used by climbing plants for support, attachment and cellular invasion by parasitic plants, generally by twining around suitable hosts. They do not have a lamina or blade, but they can photosynthesize...

    : a slender organ (modified e.g. from stem, leaf, leaflet or stipule) used by climbing plants to cling to an object.

  • tepal
    Tepals are elements of the perianth, or outer part of a flower, which include the petals or sepals. The term tepal is more often applied specifically when all segments of the perianth are of similar shape and color, or undifferentiated, which is called perigone...

    : perianth segment, either sepal or petal; usually used when all perianth segments are similar in appearance; cf. petal.

  • terete: circular in cross-section; more or less cylindrical.

  • terminal: situated at the tip or apex.

  • ternate: in groups of three; of leaves, arranged in whorls of three; of a single leaf, with the leaflets arranged in groups of three. See Leaf shape
    Leaf shape
    In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...


  • terrestrial
    Terrestrial plant
    A terrestrial plant is one that grows on land. Other types of plants are aquatic , epiphytic , lithophytes and aerial ....

    : generally denotes of or on the ground; of habitat, on land as opposed to in water (aquatic) or on rocks (lithophytic), or other plants (epiphytic), and so on.

  • testa: seed coat.

  • tetrad: a group of four; usually means four pollen grains remaining fused together a maturity, e.g. in the Epacridaceae.

  • tetraspore: the asexual spore of red algae. It is so named because each sporangium produces just four spores. See Rhodophyceae.

  • thorn
    Thorns, spines, and prickles
    In botanical morphology, thorns, spines, and prickles are hard structures with sharp, or at least pointed, ends. In spite of this common feature, they differ in their growth and development on the plant; they are modified versions of different plant organs, stems, stipules, leaf veins, or hairs...

    : a sharp, stiff point, usually a modified stem, that cannot be detached without tearing the subtending tissue; a spine; cf. prickle.

  • throat: the opening of a corolla or perianth.

  • thyrse: a branched inflorescence in which the main axis is indeterminate (racemose) and the lateral branches determinate (cymose).

  • tomentum
    Tomentum may refer to the following:*In botany, a covering of closely matted or fine hairs on plant leaves. *A network of minute blood vessels in the brain.* Tomentum in zoology are a short, soft pubescence...

    (adjective tomentose): a dense covering of short, matted hairs. Tomentose is often used as a general term for bearing an indumentum, but this is not a recommended use.

  • toothed: with a more or less regularly incised margin.

  • torus: see receptacle.

  • trademark
    A trademark, trade mark, or trade-mark is a distinctive sign or indicator used by an individual, business organization, or other legal entity to identify that the products or services to consumers with which the trademark appears originate from a unique source, and to distinguish its products or...

    (trade mark): a distinctive word, picture, symbol, smell or other device or any combination or multiples of these. It must not be descriptive of the goods or services, nor can it be geographical nor a surname. Used to distinguish one trader from another, compared with PBR which protect the commercial name of a particular plant variety.

trapeziform: (1) like a trapezium
In Euclidean geometry, a convex quadrilateral with one pair of parallel sides is referred to as a trapezoid in American English and as a trapezium in English outside North America. A trapezoid with vertices ABCD is denoted...

 (a four-sided figure with two parallel sides of unequal length); (2) like a trapezoid (a four-sided figure, or quadrilateral
In Euclidean plane geometry, a quadrilateral is a polygon with four sides and four vertices or corners. Sometimes, the term quadrangle is used, by analogy with triangle, and sometimes tetragon for consistency with pentagon , hexagon and so on...

, with neither pair of sides equal); sometimes used erroneously as a synonym for rhombic.
  • tree
    A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

    : a woody plant, usually with a single distinct trunk and generally more than 5 m tall.

  • triad: a group of three.

  • triangular: planar and with 3 sides.

  • tribe
    Tribe (biology)
    In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...

    : a taxonomic grouping, in rank between genus and species.

  • trichome
    Trichomes are fine outgrowths or appendages on plants and certain protists. These are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae.- Algal trichomes :...

    : in non-filamentous plants, any hair-like outgrowth from epidermis, e.g. a hair or bristle; sometimes restricted to unbranched epidermal outgrowths.

  • trifoliolate (or trifoliate): a compound leaf of three leaflets, for example a clover
    Clover , or trefoil, is a genus of about 300 species of plants in the leguminous pea family Fabaceae. The genus has a cosmopolitan distribution; the highest diversity is found in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes...


  • trigonous: triangular in cross-section and obtusely angled; cf. triquetus.

  • trinerved: having three nerves or veins.

  • triplinerved: (of leaves) having three main nerves with the lateral nerves arising from the midnerve above the base of the leaf.

  • triquetrous: more or less triangular in cross-section, but acutely angled (with 3 distinct longitudinal ridges); cf. trigonus.

  • trivial name
    Trivial name
    In chemistry, a trivial name is a common name or vernacular name; it is a non-systematic name or non-scientific name. That is, the name is not recognised according to the rules of any formal system of nomenclature...

    : the second word in the two-part scientific name of an organism; cf. specific epithet.

trullate: ovate but angled; like a bricklayer's trowel
A trowel is one of several similar hand tools used for digging, smoothing, or otherwise moving around small amounts of viscous or particulate material.-Hand tools:...

; inverse kite
Kite (geometry)
In Euclidean geometry a kite is a quadrilateral whose four sides can be grouped into two pairs of equal-length sides that are next to each other. In contrast, a parallelogram also has two pairs of equal-length sides, but they are opposite each other rather than next to each other...

-shaped; compare rhombic.
  • truncate: cut off squarely; with an abruptly transverse end.

Trunk (botany)
In botany, trunk refers to the main wooden axis of a tree that supports the branches and is supported by and directly attached to the roots. The trunk is covered by the bark, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the...

: the upright large main stem of a tree.
  • truss: a compact cluster of flowers or fruits arising from one centre; for instance, evident in many rhododendron
    Rhododendron is a genus of over 1 000 species of woody plants in the heath family, most with showy flowers...


Tubers are various types of modified plant structures that are enlarged to store nutrients. They are used by plants to survive the winter or dry months and provide energy and nutrients for regrowth during the next growing season and they are a means of asexual reproduction...

: an underground storage organ formed by the swelling of an underground stem which produces buds and stores food, forming a seasonal perennating organ, for example potato
The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...

; compare tuberoid.
  • tubercle
    A tubercle is generally a wart-like projection, but it has slightly different meaning depending on which family of plants or animals it is used to refer to....

    : a small wart
    A wart is generally a small, rough growth, typically on a human’s hands or feet but often other locations, that can resemble a cauliflower or a solid blister. They are caused by a viral infection, specifically by human papillomavirus 2 and 7. There are as many as 10 varieties of warts, the most...

    -like outgrowth.

A tubercle is generally a wart-like projection, but it has slightly different meaning depending on which family of plants or animals it is used to refer to....

: covered in tubercles; warty.
tuberoid: an underground storage organ formed by the swelling of a root; occurs in many orchids.
  • tuberous: resembling a tuber; producing tubers.

  • tubular: with the form of a tube or cylinder
    Cylinder (geometry)
    A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given line segment, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder...


  • tunic: outer covering of some bulbs and corms.

  • turbinate: top
    A top is a toy that can be spun on an axis, balancing on a point. This motion is produced in the most simple forms of top by twirling the stem using the fingers. More sophisticated tops are spun by by holding the axis firmly while pulling a string or twisting a stick or pushing an auger as shown...


turgid: swollen with liquid; firm; compare flaccid.
Tussock (grass)
Tussock grasses or bunch grasses are found as native plants in natural ecosystems, as forage in pastures, and as ornamental grasses in gardens....

: a dense tuft of vegetation, usually well separated from neighbouring tussocks, for example some grasses; compare sward.
  • two-ranked: having leaves arranged in two rows in the same plane, on opposite sides of the branch; = distichous.

  • type: an item (usually a herbarium specimen) to which the name of a taxon is permanently attached, i.e. a designated representative of a plant name. Important in determining the priority of names available for a particular taxon.

  • type genus
    Type genus
    In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...

    : in nomenclature, the genus from which the family is based.

  • typography
    Typography is the art and technique of arranging type in order to make language visible. The arrangement of type involves the selection of typefaces, point size, line length, leading , adjusting the spaces between groups of letters and adjusting the space between pairs of letters...

    : the presentation of printed matter, covering issues such as type styles (e.g. italic or roman type), underlining, emboldening and letter spacing.


  • umbel
    An umbel is an inflorescence which consists of a number of short flower stalks which are equal in length and spread from a common point, somewhat like umbrella ribs....

    (adjective umbellate): a racemose inflorescence in which all the individual flower stalks arise in a cluster at the top of the peduncle and are of about equal length; in a simple umbel, each stalk is unbranched and bears only one flower; a cymose umbel is an apparent umbel but its flowers open centrifugally.

  • umbonate: with a conical projection arising from a flatter surface.

  • uncinate: with a hook at the apex.

  • undershrub: a low shrub, often with flowering branches that die off in winter; cf. subshrub.

undulate: wavy and not flat; compare sinuate.
  • unilocular: having one loculus or chamber, e.g., the ovary in the families Proteaceae and Fabaceae.

  • unisexual: of one sex; bearing only male or only female reproductive organs.

  • unitegmic: (of an ovule), covered by a single integument.

  • urceolate
    Urceolate literally means "shaped like an urn or pitcher", with a swollen middle and narrowing top. It is often used in botany to describe a feature of plant morphology. Examples of urceolate plant structures are the pitchers of many species of the pitcher plant genera Sarracenia and Nepenthes....

    : urn
    An urn is a vase, ordinarily covered, that usually has a narrowed neck above a footed pedestal. "Knife urns" placed on pedestals flanking a dining-room sideboard were an English innovation for high-style dining rooms of the late 1760s...


  • utricle: a small bladder; a membranous bladder-like sac enclosing an ovary or fruit; in sedges a fruit in which the pericarp is larger than, and loosely encloses, the seed.


  • valvate: of sepals and petals in bud, which meet edge to edge but do not overlap.

  • valve: a portion of an organ that fragments or splits open, for example the teeth-like portions of a pericarp in a split (dehisced) capsule.

  • var.: see varietas.

  • variant: a plant or group of plants showing some measure of difference from the characteristics associated with a particular taxon.

  • varietas (variety in common usage, abbreviated as var.): (Latin) in the Linnean hierarchy a rank below that of species, between the ranks of subspecies and form.

  • variegated: irregularly marked with blotches or patches of another colour.

  • Vasculum
    A vasculum is a container used by botanists to keep field samples viable by maintaining a cool, humid environment. Vascula are typically flattened tin cylinders, carried horizontally on a strap so that specimens lie flat and lined with moistened cloth....

    : Container used by botanists for collecting field specimines.

vein: a strand of vascular tissue; nerve.
  • veinlet: a small vein; the ultimate (visible) division of a vein.

  • velvety: densely covered with fine, short, soft, erect hairs.

  • venation: the arrangement of veins in a leaf.

  • ventral: the front; in particular, towards the axis in a lateral organ or towards substratum in prostrate plant; compare dorsal.

  • vernation
    Vernation is the formation of new leaves or fronds. In plant anatomy, it is the arrangement of leaves in a bud....

    : the arrangement of unexpanded leaves in a bud; the order of unfolding of leaves from a bud.

  • verrucose: with warts.

  • versatile: of anthers, swinging freely about the point of attachment to the filament.

  • verticillate: arranged in one or more whorls.

  • vescicular: of hairs, bladder-like; vesciculous, bearing such hairs.

  • vessel
    Vessel element
    A vessel element is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are typically found in the angiosperms but absent from most gymnosperms such as the conifers....

    : a capillary tube formed from a series of open-ended cells in the water-conducting tissue of a plant.

vestigial: reduced in form and function from the normal or ancestral condition.
  • villous: covered with long, soft, weak hairs, the covering somewhat dense.

  • vine
    A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...

    : 1) Vitis
    Vitis is a genus of about 60 species of vining plants in the flowering plant family Vitaceae. The genus is made up of species predominantly from the Northern hemisphere. It is economically important as the source of grapes, both for direct consumption of the fruit and for fermentation to produce...

    . 2) Scandent
    A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...

     plants climbing by means of trailing or twining stem or runner. 3) Such a stem or runner

  • viscid: sticky; coated with a thick, syrupy secretion.

  • viviparous: (1) seeds or fruits which germinate before being shed from the parent plant, (2) the development of plantlets on non-floral organs e.g. leaves.


warty: a surface covered with small round protuberances, especially in fruit, leaves, twigs and bark, see tuberculate.
  • watershoot: an erect strong-growing or epicormic shoot developing from near the base of a shrub or tree, but distinct from a sucker.

A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...

: loosely defined as a plant growing where it is not wanted; commonly associated with disrupted habitats; (1) agricultural weed: a plant which taints produce or pollutes crops; (2) environmental weed: naturalised, exotic or ecologically 'out-of-balance' indigenous species outside the agricultural or garden context which, as a result of invasion, adversely affects the survival or regeneration of indigenous species in natural or partly natural vegetation communities (Carr, G.W., in Foreman & Walsh, 1993).
  • wild: originating from a known wild habitat (wilderness
    Wilderness or wildland is a natural environment on Earth that has not been significantly modified by human activity. It may also be defined as: "The most intact, undisturbed wild natural areas left on our planet—those last truly wild places that humans do not control and have not developed with...

    ). See Wildlife
    Wildlife includes all non-domesticated plants, animals and other organisms. Domesticating wild plant and animal species for human benefit has occurred many times all over the planet, and has a major impact on the environment, both positive and negative....


Whorl (botany)
In botany, a whorl is an arrangement of sepals, petals, leaves, or branches in which all the parts are attached at the same point and surround or wrap around the stem.There are four whorls in a general flower...

: a ring of organs borne at the same level on an axis, for example leaves, bracts or floral parts.
  • wing:
  1. a membranous expansion of a fruit or seed which aids in dispersal, for instance on pine
    Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...

  2. a thin flange of tissue extending beyond the normal outline of a structure, e.g. on the column of some orchids, on stems, on petioles;
  3. one of the two lateral petals of a flower of subfamily Faboideae
    Faboideae is a subfamily of the flowering plant family Fabaceae or Leguminosae. One acceptable alternative name for the subfamily is Papilionoideae....

     of family Fabaceae
    The Fabaceae or Leguminosae, commonly known as the legume, pea, or bean family, is a large and economically important family of flowering plants. The group is the third largest land plant family, behind only the Orchidaceae and Asteraceae, with 730 genera and over 19,400 species...

    , located between the adaxial standard (banner) petal and the two abaxial keel petals.

  • woolly: very densely covered with long, more or less matted or intertwined hairs, resembling sheep's wool
    Wool is the textile fiber obtained from sheep and certain other animals, including cashmere from goats, mohair from goats, qiviut from muskoxen, vicuña, alpaca, camel from animals in the camel family, and angora from rabbits....



  • xeromorph: a plant with structural features (e.g. hard or succulent leaves) or functional adaptations that prevent water loss by evaporation; usually associated with arid habitats, but not necessarily drought-tolerant; cf. xerophyte.

  • xerophyte
    A xerophyte or xerophytic organism is a plant which has adapted to survive in an environment that lacks water, such as a desert. Xerophytic plants may have adapted shapes and forms or internal functions that reduce their water loss or store water during long periods of dryness...

    : a plant generally living in a dry habitat, typically showing xeromorphic or succulent adaptation; a plant able to tolerate long periods of drought; cf. xeromorph.


zygomorphic: bilaterally symmetrical; symmetrical about one vertical plane only; applies to flowers in which the perianth segments within each whorl vary in size and shape; compare actinomorphic, irregular.
  • zygote
    A zygote , or zygocyte, is the initial cell formed when two gamete cells are joined by means of sexual reproduction. In multicellular organisms, it is the earliest developmental stage of the embryo...

    : a fertilized cell.

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