The Fabaceae is a very large and importamt family of 650 genera and over 18,000 species of dicotyledenous flowering herbs and trees, commonly called legumes or pulses. The family is numerically the third largest after Orchidaceae and Asteraceae respectively. Flowers have five petals and a superior ovary. One of the unifying characteristics is the dehiscent seed pod with seeds present in a row, sometimes in individual sections. Flowers have 10 or more stamens. A common feature is symbiosis with nitrogen-fixing bacteria, which reside in special root nodules and fix atmospheric nitrogen to nitrate assisting the plants' growth on poor soils. When used as a green manure they add nitrogen to the soil.
The Fabaceae are of great agricultural importance as food crops (beans, lentils, peanuts, peas, soybeans) and fodder crops or green manure (alfafa, clover, lupins, soybean). However, many species contain toxic lectins and other poisons in their seeds. Even with edible pulses, it is advisable to boil them vigorously to destroy their lectins. The family includes many ornamental (Acacia, Laburnum, Mimosa) and xerophytic trees (Acacia, Mesquite, Paolo Verde), distributed across both the Old and New Worlds.
Succulent genera: Cassia, Dolichos, Elephantorrhiza, Erythrina, Neorautenania, Senna.