Pelargonium
Overview
 
Pelargonium ˌ is a genus
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...

 of flowering plant
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 which includes about 200 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...

 of perennial
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

s, succulent
Succulent plant
Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to arid climates or soil conditions. Succulent plants store water in their leaves, stems, and also in roots...

s, and shrub
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...

s, commonly known as scented geraniums or storksbills. Confusingly, Geranium is the correct botanical name of a separate genus of related plants often called Cranesbill
Cranesbill
Geranium is a genus of 422 species of flowering annual, biennial, and perennial plants that are commonly known as the cranesbills. It is found throughout the temperate regions of the world and the mountains of the tropics, but mostly in the eastern part of the Mediterranean region. The long,...

s. Both Geranium and Pelargonium are genera in the Family Geraniaceae
Geraniaceae
Geraniaceae is a family of flowering plants placed in the order Geraniales. The family name is derived from the genus Geranium. It includes both the genus Geranium and the garden plants called geraniums, which modern botany classifies as genus Pelargonium, along with other related genera.There are...

. Linnaeus
Carolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...

 originally included all the species in one genus, Geranium, but they were later separated into two genera by Charles L’Héritier
Charles Louis L'Héritier de Brutelle
Charles Louis L'Héritier de Brutelle was an 18th century French botanist and magistrate. Born into an affluent upper-class Parisian family, connections with the French Royal Court secured him the position of Superindent of Parisian Waters and Forests at the age of twenty-six...

 in 1789.
Encyclopedia
Pelargonium ˌ is a genus
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...

 of flowering plant
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 which includes about 200 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...

 of perennial
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...

s, succulent
Succulent plant
Succulent plants, also known as succulents or fat plants, are water-retaining plants adapted to arid climates or soil conditions. Succulent plants store water in their leaves, stems, and also in roots...

s, and shrub
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...

s, commonly known as scented geraniums or storksbills. Confusingly, Geranium is the correct botanical name of a separate genus of related plants often called Cranesbill
Cranesbill
Geranium is a genus of 422 species of flowering annual, biennial, and perennial plants that are commonly known as the cranesbills. It is found throughout the temperate regions of the world and the mountains of the tropics, but mostly in the eastern part of the Mediterranean region. The long,...

s. Both Geranium and Pelargonium are genera in the Family Geraniaceae
Geraniaceae
Geraniaceae is a family of flowering plants placed in the order Geraniales. The family name is derived from the genus Geranium. It includes both the genus Geranium and the garden plants called geraniums, which modern botany classifies as genus Pelargonium, along with other related genera.There are...

. Linnaeus
Carolus Linnaeus
Carl Linnaeus , also known after his ennoblement as , was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature. He is known as the father of modern taxonomy, and is also considered one of the fathers of modern ecology...

 originally included all the species in one genus, Geranium, but they were later separated into two genera by Charles L’Héritier
Charles Louis L'Héritier de Brutelle
Charles Louis L'Héritier de Brutelle was an 18th century French botanist and magistrate. Born into an affluent upper-class Parisian family, connections with the French Royal Court secured him the position of Superindent of Parisian Waters and Forests at the age of twenty-six...

 in 1789. Gardeners sometimes refer to the members of Genus Pelargonium as "pelargoniums" in order to avoid the confusion, but the older common name "geranium" is still in regular use, and most garden 'geraniums' are in fact 'pelargoniums', as opposed to true geraniums or cranesbill.

Species of Pelargonium are evergreen perennials indigenous to Southern Africa and are drought and heat tolerant, and can tolerate only minor frosts. Pelargoniums are extremely popular garden
Garden
A garden is a planned space, usually outdoors, set aside for the display, cultivation, and enjoyment of plants and other forms of nature. The garden can incorporate both natural and man-made materials. The most common form today is known as a residential garden, but the term garden has...

 plants, grown as annuals in temperate climates.

History

The first species of Pelargonium known to be cultivated was Pelargonium triste, a native of South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

. It was probably brought to the botanical garden
Botanical garden
A botanical garden The terms botanic and botanical, and garden or gardens are used more-or-less interchangeably, although the word botanic is generally reserved for the earlier, more traditional gardens. is a well-tended area displaying a wide range of plants labelled with their botanical names...

 in Leiden before 1600 on ships which stopped at the Cape of Good Hope
Cape of Good Hope
The Cape of Good Hope is a rocky headland on the Atlantic coast of the Cape Peninsula, South Africa.There is a misconception that the Cape of Good Hope is the southern tip of Africa, because it was once believed to be the dividing point between the Atlantic and Indian Oceans. In fact, the...

. In 1631, the English gardener John Tradescant the elder
John Tradescant the elder
John Tradescant the elder , father of John Tradescant the younger, was an English naturalist, gardener, collector and traveller, probably born in Suffolk, England...

 bought seeds from Rene Morin
René Morin
Louis-Simon-René Morin was head of the Canadian Broadcasting Corporation during World War II from 1940 to 1944, and was the first francophone to head of the CBC....

 in Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

 and introduced the plant to England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. The name Pelargonium was introduced by Johannes Burman
Johannes Burman
Johannes Burman , was a Dutch botanist and physician. Burman specialized in plants from Ceylon, Amboina and Cape Colony. The name Pelargonium was introduced by Johannes Burman....

 in 1738, from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 πελαργός, pelargós, stork
Stork
Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family Ciconiidae. They are the only family in the biological order Ciconiiformes, which was once much larger and held a number of families....

, because the seed head looks like a stork's beak.

Structure

Pelargonium 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....

 are usually alternate, and palmately
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...

 lobed or pinnate
Pinnate
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...

, often on long stalks, and sometimes with light or dark patterns.
The erect stems bear five-petaled flower
Flower
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...

s in umbel
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....

-like clusters called pseudoumbels. The shapes of the flowers have been bred to a variety ranging star-shaped to funnel-shaped, and colors include white, pink, red, orange-red, fuchsia to deep purple. The Pelargonium flower has a single symmetry plane (zygomorphic), which distinguishes it from the Geranium flower which has radial symmetry (actinomorphic).

Distribution

The Mediterranean climate of southern Africa and Australia, and the north of New Zealand. Others are native to southern Madagascar, eastern Africa, Yemen, Asia Minor and two very isolated islands in the south Atlantic ocean (St. Helena and Tristan da Cunha). Most of the Pelargoniums cultivated in Europe and North America have their origins in South Africa.

Classification

There is considerable confusion as to which Pelargoniums are true species, cultivars, or hybrids. The nomenclature has changed considerably since the first Pelargoniums were introduced to Europe in the seventeenth century.

Species

Commonly found are: Pelargonium crispum, Pelargonium cucullatum
Pelargonium cucullatum
Pelargonium cucullatum is a species of plant in the Geraniaceae family, that is indigenous to the south-western Cape of South Africa...

, Pelargonium echinatum, Pelargonium grandicalcaratum, Pelargonium graveolens
Pelargonium graveolens
Pelargonium graveolens is a species in the Pelargonium genus, which is indigenous to various parts of southern Africa, and in particular South Africa. It is often called geranium as it falls within the plant family Geraniaceae, although more correctly, it is referred to as Pelargonium. This...

, Pelargonium magenteum, Pelargonium x nervosum, Pelargonium odorantissimum, Pelargonium peltatum
Pelargonium peltatum
Pelargonium peltatum is a species of geranium known by the common names ivy-leaf geranium and cascading geranium. It is native to southern Africa, particularly South Africa. It is commonly grown as an ornamental plant. This is a subshrub which can reach two meters in height, its branches prostrate,...

, Pelargonium quercifolium
Pelargonium quercifolium
Pelargonium quercifolium is a species of geranium known by the common name oakleaf geranium. It is native to South Africa, and it is a commonly grown ornamental plant. This is a densely branching shrub easily exceeding one meter in height, taller than wide. The stems are soft and coated in green...

, Pelargonium tomentosum, Pelargonium tricolor, Pelargonium xerophyton, Pelargonium zonale.

Cultivars and hybrids

Horticultural pelargoniums (as opposed to botanical, the wild 'species') fall into six major groups, with zonals subdivided further. Thousands of ornamental cultivar
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...

s have been developed from about 20 of the species.

The nine major groups are;

- Zonals which cover:
.. Fancy Leaf: Gold Leaf, Silver Leaf, Butterfly Leaf & Tri-Colour
.. Fancy Flowered: Carnation Flowered, Tulip Flowered, Cactus Flowered, Rosebud Flowered
.. Dwarf Zonals which are no taller than 8" when grown in a 4" pot
.. Miniature Zonals which are no taller than 5" when grown in a 4" pot

- Angels (sometimes called miniature regals but they are not)

- Ivy-leaved (the varieties that trail and are used in hanging baskets or window boxes)

- Ivy x Zonals: a hybrid cross of ivy leaf and zonals

- Regals (sometimes wrongly referred to as 'Martha Washingtons')

- Uniques

- Formosum

- Frutetorum Hybrids

- Stellars
Ivy-leaved (Hanging) varieties are mainly derived from P. peltatum
Pelargonium peltatum
Pelargonium peltatum is a species of geranium known by the common names ivy-leaf geranium and cascading geranium. It is native to southern Africa, particularly South Africa. It is commonly grown as an ornamental plant. This is a subshrub which can reach two meters in height, its branches prostrate,...

. Hanging stems and hardened leaves, used in hanging baskets.

Regal (Royal, French) varieties or P. × domesticum are mainly derived from P. cucullatum and P. grandiflorum. They have woody stems, wrinkled leaves and pointed lobes, and are mainly grown in greenhouses.

Zonal varieties, also known as P. × hortorum, are mainly derived from P. zonale and P. inquinans. They have round leaves with a coloured spot in the centre (hence Zonal).

The Garden geranium (Pelargonium x hortorum; syn. Pelargonium zonale) is one of the most common ornamental potted-plants, with over 500 varieties.

Scented 'geraniums'

Scented-leaf varieties are derived from a great number of species, amongst others P. graveolens. These include;
Species
  • Almond - Pelargonium quercifolium
    Pelargonium quercifolium
    Pelargonium quercifolium is a species of geranium known by the common name oakleaf geranium. It is native to South Africa, and it is a commonly grown ornamental plant. This is a densely branching shrub easily exceeding one meter in height, taller than wide. The stems are soft and coated in green...

  • Apple - Pelargonium odoratissimum
  • Coconut - Pelargonium grossalarioides (Pelargonium parriflorum)
  • Lemon - Pelargonium crispum
  • Nutmeg - Pelargonium fragrans (Pelargonium x fragrans)
  • Old Spice - Pelargonium fragrans 'Logees'
  • Peppermint - Pelargonium tomentosum
  • Rose - Pelargonium graveolens
    Pelargonium graveolens
    Pelargonium graveolens is a species in the Pelargonium genus, which is indigenous to various parts of southern Africa, and in particular South Africa. It is often called geranium as it falls within the plant family Geraniaceae, although more correctly, it is referred to as Pelargonium. This...

     (Pelargonium roseum)
  • Rose - Pelargonium capitatum
    Pelargonium capitatum
    Pelargonium capitatum is one of several species known as rose-scented pelargonium in English. The popular names refer to the scent of the essential oils extracted from glandular tissue, not the flowers, which have hardly any scent to speak of. Some of the species are known as kusmalva in...

  • Rose - Pelargonium radens
    Pelargonium radens
    Pelargonium radens is a species of Pelargonium. It is an evergreen perennial plant, growing to about three feet high. It has deeply-cut triangular scented gray-green leaves and in the summer bears clusters of small pink-purple flowers, followed by small curly-tailed brownish seeds. Traditionally...

  • Lemon Scented - Pelargonium citronellum
  • Southernwood - Pelargonium abrotanifolium
  • Strawberry - Pelargonium scarboroviae (Pelargonium x scarboroviae)
  • Pelargonium ionidiflorum
  • Fiery flowered stork's bill Pelargonium ignescens Scarlet Unique Scented Geranium


Cultivars
  • 'Attar of Roses' - a cultivar of the Rose Geranium (Pelargonium capitatum
    Pelargonium capitatum
    Pelargonium capitatum is one of several species known as rose-scented pelargonium in English. The popular names refer to the scent of the essential oils extracted from glandular tissue, not the flowers, which have hardly any scent to speak of. Some of the species are known as kusmalva in...

    )
  • 'Crowfoot Rose' - a cultivar of the Rose Geranium (Pelargonium radens
    Pelargonium radens
    Pelargonium radens is a species of Pelargonium. It is an evergreen perennial plant, growing to about three feet high. It has deeply-cut triangular scented gray-green leaves and in the summer bears clusters of small pink-purple flowers, followed by small curly-tailed brownish seeds. Traditionally...

    )
  • 'Dr. Livingston' - a cultivar of the Rose Geranium (Pelargonium radens
    Pelargonium radens
    Pelargonium radens is a species of Pelargonium. It is an evergreen perennial plant, growing to about three feet high. It has deeply-cut triangular scented gray-green leaves and in the summer bears clusters of small pink-purple flowers, followed by small curly-tailed brownish seeds. Traditionally...

    )
  • 'Grey Lady Plymouth' - a cultivar of the Rose Geranium (Pelargonium graveolens
    Pelargonium graveolens
    Pelargonium graveolens is a species in the Pelargonium genus, which is indigenous to various parts of southern Africa, and in particular South Africa. It is often called geranium as it falls within the plant family Geraniaceae, although more correctly, it is referred to as Pelargonium. This...

    )
  • 'Prince Rupert' - a cultivated variety of the Lemon Geranium ( Pelargonium crispum)


Hybrids
  • 'Ginger' - Pelargonium x torento (Pelargonium torento)
  • 'Lemon Balm' - a hybrid: Pelargonium x melissinum (Pelargonium melissinum)
  • 'Lime' - a hybrid: (Pelargonium x nervosum) (Pelargonium nervosum)
  • 'Prince of Orange' - a hybrid: Pelargonium x citrosum


Usage

Other than being grown for their beauty, species of Pelargonium such as P. graveolens
Pelargonium graveolens
Pelargonium graveolens is a species in the Pelargonium genus, which is indigenous to various parts of southern Africa, and in particular South Africa. It is often called geranium as it falls within the plant family Geraniaceae, although more correctly, it is referred to as Pelargonium. This...

 are important in the perfume
Perfume
Perfume is a mixture of fragrant essential oils and/or aroma compounds, fixatives, and solvents used to give the human body, animals, objects, and living spaces "a pleasant scent"...

 industry and are cultivated and distilled
Distillation
Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....

 for its scent. Although scented Pelargonium exist which have smells of citrus
Citrus
Citrus is a common term and genus of flowering plants in the rue family, Rutaceae. Citrus is believed to have originated in the part of Southeast Asia bordered by Northeastern India, Myanmar and the Yunnan province of China...

, mint
Mentha
Mentha is a genus of flowering plants in the family Lamiaceae . The species are not clearly distinct and estimates of the number of species varies from 13 to 18. Hybridization between some of the species occurs naturally...

, pine, spices or various fruits, the varieties with rose
Rose
A rose is a woody perennial of the genus Rosa, within the family Rosaceae. There are over 100 species. They form a group of erect shrubs, and climbing or trailing plants, with stems that are often armed with sharp prickles. Flowers are large and showy, in colours ranging from white through yellows...

 scents are most commercially important. Pelargonium distillates and absolutes, commonly known as "scented geranium oil" are sometimes used to supplement or adulterate expensive rose oil
Rose oil
Rose oil, meaning either rose otto or rose absolute, is the essential oil extracted from the petals of various types of rose...

s. The edible leaves and flowers are also used as a flavouring in desserts, cakes, jellies and teas. Studies show that Pelargonium sidoides
Pelargonium sidoides
Pelargonium sidoides is a medicinal plant native to South Africa. Derivative inexpensive cold and flu medicines of various brands are widely available under the Umcka name....

 is effective for cough.

Pelargoniums and insects

Pelargonium species are used as food plants by the larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...

e of some Lepidoptera
Lepidoptera
Lepidoptera is a large order of insects that includes moths and butterflies . It is one of the most widespread and widely recognizable insect orders in the world, encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...

 species including Angle Shades
Angle Shades
The Angle Shades is a moth of the family Noctuidae. It is a common and familiar European species and is often strongly migratory....

. Pelargoniums are believed to deter mosquitoes.

The Japanese beetle
Japanese beetle
The beetle species Popillia japonica is commonly known as the Japanese beetle. It is about long and wide, with iridescent copper-colored elytra and green thorax and head...

, an important agricultural insect pest, becomes rapidly paralyzed after consuming flower petals of zonal geranium (Pelargonium x hortorum). The phenomenon was first described in 1920, and subsequently confirmed. Research conducted by Dr. Christopher Ranger with the USDA Agricultural Research Service
Agricultural Research Service
The Agricultural Research Service is the principal in-house research agency of the United States Department of Agriculture . ARS is one of four agencies in USDA's Research, Education and Economics mission area...

 and other collaborating scientists have demonstrated an excitatory amino acid called quisqualic acid
Quisqualic acid
Quisqualic acid is an agonist for both AMPA receptors and group I metabotropic glutamate receptors. It causes excitotoxicity and is used in neuroscience to selectively destroy neurons in the brain or spinal cord...

 is present within the flower petals and is responsible for causing paralysis of the Japanese beetle. Quisqualic acid is thought to mimic L-glutamic acid, which is a neurotransmitter
Neurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...

 in the insect neuromuscular junction and mammalian central nervous system.

Diseases

  • Pelargonium flower break virus
    Pelargonium flower break virus
    Pelargonium flower break virus is a plant pathogenic virus of the family Tombusviridae.-External links:**...

  • Pelargonium line pattern virus
    Pelargonium line pattern virus
    Pelargonium line pattern virus is a plant pathogenic virus of the family Tombusviridae.-External links:**...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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