Leguminosae

Leguminosae, a large. natural order of dicotyledonous plants, comprising some 7,000 species in about 550 genera. They occur in all parts of the globe; but are specially abundant in the tropics. Including plants of all sizes, the order - one of the first recognised as natural - agrees in having scattered, stipulate leaves, generally compound; an inferior calyx of five united sepals, of which the odd one is anterior - thus differing from that of the Rosaoeae (q.v.) - five free perigynous petals; stamens ten, and monadelphous or diadelphous, or indefinite in number and free; and almost always a single superior many-seeded carpel which forms a legume (q.v.), and contains exalbuminous seeds with large cotyledons. The order is divided into three sub-orders: the Papilionacea, to which all British, and most European, members of the order belong, named from its butterfly-like corolla (q.v.), with one large posterior petal or standard, two lateral or wing petals, and two, sometimes united, keel petals, and ten stamens; the Ca-salpiniece, with monosymmetric but not papilionaceous corollas and ten stamens; and the Mimosece, with polysymmetric flowers having valvate petals and an indefinite number of stamens. No order except, the grasses, and perhaps the palms, is so useful'to man. Besides some valuable timbers and fibres, it yields such important dyes as indigo (q.v.) and logwood (q.v.); the chief gums, including gum-arabic, gum-tragacanth and wattle-gums; such fodder plants as clover, lucerne, and sainfoin; and, most useful of all, the pulses, peas,. beans, lentils, etc., so rich in nitrogenous matter.. The order is, in fact, often spoken of as the pea and bean tribe. Several members of the order are poisonous, especially in their seeds, as the laburnum (q.v.), and the Calabar or ordeal bean (Physostigma venenosum).