Papilionaceæ

Papilionaceæ (from Lat. papilio, 'butterfly'), a sub-order of the natural order of plants generally called Leguminosæ (q.v.), the plants of which have flowers of the peculiar structure called papilionaceous, and of which the Pea and Bean afford familiar examples. Papilionaceous flowers have five petals, imbricated in estivation (bud), one of which, called the vexillum, or standard, is superior, turned next to the axis, and in estivation folded over the rest; two, called the ala, or wings, are lateral; and two are inferior, which are often united by their lower margins, forming the carina, or keel. The number of the Papilionaceæ is very great—about 4800 species being known. They are found in all parts of the world, abounding in the tropics. Many have superb and beautiful flowers; many are plants of beautiful form and foliage, trees, shrubs, or herbaceous plants; many possess valuable medicinal properties; and many are of great importance as furnishing food for man and for domestic animals, others as furnishing dyes, fibre, timber, &c. See BROOM, LABURNUM, CLOVER, BEAN, PEA, LUCERNE, LIQUORICE, INDIGO, SANDALWOOD, &c.