Fascicle (botany)
Encyclopedia
In botany
, a fascicle (sometimes short shoot) is a bundle of leaves
or flowers, or of the vascular tissue
s that supply these organs with nutrients. Vascular tissues may be in fascicles even when the organs supplied by them are not.
The term fascicle is used also in a more general sense; that sense is outside the scope of this article.
s, and the number of adult leaves (needles) per fascicle is an important character for identification of pine species
and genera
. Most species have fascicles of 2 to 5 needles; only single species usually have fascicles of 1 or 6.
Variation is high between species, low within them. For example, Pinus flexilis (limber pine
), has fascicles of 5 needles. This pine is a member of the white pine
group, Pinus subgenus Strobus, section Strobus. In all members of the group the fascicles have five needles and the sheath at the base of the fascicle is deciduous.
The fascicle sheath is another character that is important for identification. Among North America
n pines the sheath is persistent in all so-called hard pines and deciduous in all so-called soft pines. Thus, the fascicle sheath and number of needles can be used to identify valuable timber
pines in all seasons and many years before they are mature enough to produce cones. These two characters readily distinguish the major groups of pines (see Pinus classification
).
Pinus durangensis (Durango pine
) has fascicles of 6 needles, rarely 7, and is the only species in Pinus with so many needles per fascicle. Pinus monophylla has fascicles of one needle, rarely two. This is the only species of pine with just one needle per fascicle, and this rare and easily observed character is reflected in the specific epithet monophylla and common vernacular name single-leaf pinyon
.
Fascicles are present in a small number of flowering plant
s. Both leaf and flower fascicles occur, but are rare. Consequently, when fascicles are present the specific epithet tends to refer to them. Examples include Prunus fasciculata
and Adenostoma fasciculatum
. Species with flowers in fascicles include Aechmea biflora
and Melicytus ramiflorus
, several species of Malva
, and the entire genus Flueggea. Some species of the family Alseuosmiaceae
have flowers in fascicles.
In the Bignoniaceae in the genus Rhigozum
flowers are borne in fascicles from cushion-like, dwarf branchlets in the axils of leaves, and several species also bear leaves in fascicles on similar or shared branchlets.
In Opuntia
cacti, spines are produced in fascicle of a few long spines and many short spines ( or glochid
s]].
Botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...
, a fascicle (sometimes short shoot) is a bundle of leaves
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....
or flowers, or of the vascular tissue
Vascular tissue
Vascular tissue is a complex conducting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. There are also two meristems associated with vascular tissue:...
s that supply these organs with nutrients. Vascular tissues may be in fascicles even when the organs supplied by them are not.
The term fascicle is used also in a more general sense; that sense is outside the scope of this article.
In pines
Leaf fascicles are present in all pinePine
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:...
s, and the number of adult leaves (needles) per fascicle is an important character for identification of pine species
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...
and genera
Genus
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...
. Most species have fascicles of 2 to 5 needles; only single species usually have fascicles of 1 or 6.
Variation is high between species, low within them. For example, Pinus flexilis (limber pine
Limber Pine
The Limber Pine, Pinus flexilis, is a species of pine tree-the family Pinaceae that occurs in the mountains of the Western United States, Mexico, and Canada. It is also called Southwestern White Pine and Rocky Mountain White Pine...
), has fascicles of 5 needles. This pine is a member of the white pine
Pinus classification
There are three main subgenera of Pinus, the subgenus Strobus , the subgenus Ducampopinus , and the subgenus Pinus...
group, Pinus subgenus Strobus, section Strobus. In all members of the group the fascicles have five needles and the sheath at the base of the fascicle is deciduous.
The fascicle sheath is another character that is important for identification. Among North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n pines the sheath is persistent in all so-called hard pines and deciduous in all so-called soft pines. Thus, the fascicle sheath and number of needles can be used to identify valuable timber
Timber
Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...
pines in all seasons and many years before they are mature enough to produce cones. These two characters readily distinguish the major groups of pines (see Pinus classification
Pinus classification
There are three main subgenera of Pinus, the subgenus Strobus , the subgenus Ducampopinus , and the subgenus Pinus...
).
Pinus durangensis (Durango pine
Durango Pine
Durango Pine is a pine native to the Sierra Madre Occidental mountains of northwestern Mexico, from Chihuahua and Sonora south through Durango and Jalisco to Michoacán. It is a moderately high altitude species, growing at 1500–2800 m....
) has fascicles of 6 needles, rarely 7, and is the only species in Pinus with so many needles per fascicle. Pinus monophylla has fascicles of one needle, rarely two. This is the only species of pine with just one needle per fascicle, and this rare and easily observed character is reflected in the specific epithet monophylla and common vernacular name single-leaf pinyon
Single-leaf Pinyon
The Single-leaf Pinyon, ', is a pine in the pinyon pine group, native to the United States and northwest Mexico. The range is in southernmost Idaho, western Utah, Arizona, southwest New Mexico, Nevada, eastern and southern California and northern Baja California.It occurs at moderate altitudes from...
.
In flowering plants
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
s. Both leaf and flower fascicles occur, but are rare. Consequently, when fascicles are present the specific epithet tends to refer to them. Examples include Prunus fasciculata
Prunus fasciculata
Prunus fasciculata, also known as wild almond, desert almond, or desert peach is a spiny and woody shrub producing wild almonds, native to the deserts of Arizona, California, Nevada and Utah....
and Adenostoma fasciculatum
Adenostoma fasciculatum
Adenostoma fasciculatum is a flowering plant native to California and northern Baja California. This shrub is one of the most widespread plants of the chaparral biome.-Description:...
. Species with flowers in fascicles include Aechmea biflora
Aechmea biflora
Aechmea biflora is a species of plant in the Bromeliaceae family. It is endemic to Ecuador. Its natural habitat is subtropical or tropical moist montanes...
and Melicytus ramiflorus
Melicytus ramiflorus
Melicytus ramiflorus is a small tree of the family Violaceae endemic to New Zealand.It grows up to 10 metres high with a trunk up to 60 cm in diameter, it has smooth, whitish bark and brittle twigs...
, several species of Malva
Malva
Malva is a genus of about 25–30 species of herbaceous annual, biennial, and perennial plants in the family Malvaceae , one of several closely related genera in the family to bear the common English name mallow. The genus is widespread throughout the temperate, subtropical and tropical regions of...
, and the entire genus Flueggea. Some species of the family Alseuosmiaceae
Alseuosmiaceae
Alseuosmiaceae is a plant family of the order Asterales, found in Australia, New Caledonia and New Zealand.They are shrubs with simple, alternate leaves, spiral or whorled, with entire or dentate margins. The solitary flowers are terminal or axillary, or aggregated in fascicles and rarely in...
have flowers in fascicles.
In the Bignoniaceae in the genus Rhigozum
Rhigozum
Rhigozum is a genus of thorny African bush. It is in the Bignoniaceae family....
flowers are borne in fascicles from cushion-like, dwarf branchlets in the axils of leaves, and several species also bear leaves in fascicles on similar or shared branchlets.
In Opuntia
Opuntia
Opuntia, also known as nopales or paddle cactus , is a genus in the cactus family, Cactaceae.Currently, only prickly pears are included in this genus of about 200 species distributed throughout most of the Americas. Chollas are now separated into the genus Cylindropuntia, which some still consider...
cacti, spines are produced in fascicle of a few long spines and many short spines ( or glochid
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...
s]].