The versatility of the legumes enhances their great economic importance as a food or forage. They fix nitrogen, conserve soils and provide timber, fuel and important legume crops.<P>The family is also known as the Fabaceae.<P> <P>The recognition of 1 family or 3 families within the order Leguminales may still be regarded as a matter of opinion. In general the evidence seems to support the concept of a single family, as few genera are transitional between the 3 major groups" as indicated in Polhill & Raven (1981), <I>Advances in legume systematics</I> pt 1. Their concept is accepted here and their systematic treatment followed.<P>1. Flowers regular (actinomorphic); stamens usually numerous; petals<P>       valvate, equal; embryo straight .....      Subfamily 2. MIMOSOIDEAE<P>   1. Flowers irregular (zygomorphic); stamens 10 or fewer; petals imbri<P>      cate; embryo straight or curved.<P>     2. Flowers slightly irregular; stamens 10 or fewer, free; petals sub- <P>        equal, free; adaxial petal overlapped by adjacent lateral petals,<P>        abaxial petals overlapping; embryo straight <P>                                              Subfamily 1. CAESALPINIOIDEAE<P>     2. Flowers very irregular; stamens 10, often united; petals unequal,<P>        more or less united; adaxial petal (standard) outside the adjacent<P>        lateral petals (wings), abaxial petals (keel) valvate conduplicate,<P>        often cormate; embryo curved            Subfamily 3. PAPILIONOIDEAE