geranium

Geranium
Geranium dissectum
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta
(unranked):	Eudicots
Order:	Geraniales
Family:	Geraniaceae
Genus:	Geranium L., 1753
Species
See list.

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. These attractive flowers will grow in any soil as long as it is not waterlogged. Propagation is by semi-ripe cuttings in summer, by seed, or by division in autumn or spring.

The name "cranesbill" derives from the appearance of the fruit capsule of some of the species. Species in the Geranium genus have a type of mechanism produced by the pollinated flower. The mechanism is a beak-like column that springs open when ripe and casts the seeds some distance. The fruit capsule consists of five cells each containing one seed, joined to a column produced from the center of the old flower. The common name cranesbill comes from shape of the unsprung column, which in some species is long and looks like the bill of a crane. Many species in this genus do not have a long beak-like column. The genus name is derived from the Greek γέρανος, géranos, or γερανός, geranós, crane. The long, palmately cleft leaves are broadly circular in form. Their rose, pink to blue or white flowers have 5 petals.

Cranesbills are eaten by the larvae of some Lepidoptera species including Brown-tail and Mouse Moth.

The species Geranium viscosissimum is considered to be protocarnivorous.

Pelargoniums

Confusingly, "geranium" is also the common name of members of the genus Pelargonium, which were formerly classified in the cranesbill genus. In the United States, true Geraniums are frequently distinguished from the less hardy Pelargoniums as (rather redundantly) "hardy geraniums" by gardeners and in the horticultural trade. One can make the distinction between the two by looking at the flowers: Geranium has symmetrical flowers, while Pelargonium has irregular or maculate petals. Other former members of the genus are now classified in genus Erodium, including the plants known as filarees in North America.

Cultivation

Showing the "bill" and seed dispersal mechanism of Geranium pratense

A number of geranium species are cultivated for their landscape value and for pharmaceutical products. Some of the more commonly grown species include:

• Geranium cinereum
• Geranium clarkei (Clark's geranium)
• Geranium dalmaticum
• Geranium endressii
• Geranium himalayense often sold under Geranium grandiflorum
• Geranium ibericum (Caucasus geranium),
• Geranium macrorrhizum (Bigroot cranesbill or Bigroot geranium)
• Geranium maculatum (Wild geranium)
• Geranium x magnificum (Showy geranium)
• Geranium phaeum
• Geranium platypetalum (Broad-petaled geranium)
• Geranium pratense (Meadow cranesbill)
• Geranium psilostemon
• Geranium sanguineum (Bloody cranesbill)
• Geranium sylvaticum

All the above species are perennials and generally winter hardy plants, grown for their attractive flowers and foliage. They are long lived and most have a mounding habit, with palmately lobed foliage. Some species have spreading rhizomes. They are normally grown in part shade to full sun, in well draining but moisture retentive soils, that are rich in humus. ^[1] Other perennial species that are grown for their flowers and foliage include: G. argenteum, G. eriostemon, G. farreri, G. nodosum, G. procurrens, G. pylzowianum, G. renardii, G. traversii, G. tuberosum, G. versicolor, G. wallichianum and G. wlassovianum. Some of these are not winter hardy in cold areas and are grown in specialized gardens like rock gardens.^[2] Geranium x. 'Johnson's Blue' is a hybridisation between G himalayense (Southwestern China), with G pratense (European Meadow Crane'sbill). ^[3]

Gallery

Geranium phaeum - from Thomé Flora von Deutschland, Österreich und der Schweiz 1885	Geranium platypetalum	Geranium sanguineum	Johnson's Blue, garden hybrid of Geranium pratense
Flower and seed-head of Herb Robert (Geranium robertianum)	Geranium maderense	Geranium maderense	Geranium maculatum

Wikimedia Commons has media related to: Geraniaceae

See also

• Pelargonium graveolens, from which Geranium essential oil is distilled

References

• Genus geranium in North America: the perennials

External links

• ITIS list of Geranium species
• Geranium Taxonomic Information System