Thursday 24 June 2010

Lupin



Lupins or lupines (North America) are the members of the genus Lupinus in the legume family (Fabaceae). The genus comprises between 200 and 600 species, with major centers of diversity in South America and western North America, in the Mediterranean region and Africa.
The species are mostly herbaceous perennial plants 0.3-1.5 m (1–5 ft) tall, but some are annual plants and a few are shrubs up to 3 m (10 ft) tall - see also bush lupin -, with one species (Lupinus jaimehintoniana, from the Mexican state of Oaxaca) a tree up to 8 m high with a trunk 20 cm (8 in) in diameter. They have a characteristic and easily recognised leaf shape, with soft green to grey-green leaves which in many species bear silvery hairs, often densely so. The leaf blades are usually palmately divided into 5–28 leaflets or reduced to a single leaflet in a few species of the southeastern United States. The flowers are produced in dense or open whorls on an erect spike, each flower 1-2 cm long, with a typical peaflower shape with an upper 'standard' or 'banner', two lateral 'wings' and two lower petals fused as a 'keel'. Due to the flower shape, several species are known as bluebonnets or quaker bonnets. The fruit is a pod containing several seeds.
Like most members of their family, lupins can fix nitrogen from the atmosphere into ammonia via a rhizobium-root nodule symbiosis, fertilizing the soil for other plants, this adaption allows lupins to be tolerant of infertile soils and capable of pioneering change in barren and poor quality soils. The genus Lupinus is nodulated by Bradyrhizobium soil bacteria. Some species have a long central tap roots, or have proteoid roots.
Lupins contain significant amounts of certain secondary compounds like isoflavones and toxic alkaloids, e.g. lupinine and sparteine.

Bluebonnet lupins, notably the Texas Bluebonnet (Lupinus texensis) are the state flower of Texas, USA.

Photograph Details: Nikon D40, focal length 55mm, ISO-220, exp: 1/60sec, f-stop 8

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