Slenderleaf (Crotalaria brevidens Benth.) is a tropical legume mostly cultivated for food (Abukutsa-Onyango, 2004; Duke, 1981). Unlike other Crotalaria species, its toxicity level is regarded as low and it can safely be used for forage.
Crotalaria brevidens is an annual or short-lived perennial legume reaching a height of 0.4-2 m. It is erect or decumbent, and much-branched. The stems are ascending with short hairs. The leaves are alternate, trifoliolate and borne on 2-6 cm long petioles. The leaflets are linear to lanceolate, 4-14 cm long x 0.3-3.3 cm wide, hairy on their lower face. The inflorescences are apical racemes, 10-48 cm in length. They bear numerous, closely arranged papillonaceous, cream to clear yellow, veined reddish-brown flowers. The fruits are narrow, cylindrical, pubescent pods, 35-50 mm long x 5-7 mm broad, containing about 80 seeds. The seeds are smooth, small, 2-2.5 mm long x 1.5-2 mm broad, cordiform, very variable in colour (from medium yellow to orange yellow, red to dark brown or dark grey-blue. The 1000 seed-weight is 5 g (Abukutsa-Onyango, 2004; Duke, 1981).
Slenderleaf is mainly a food legume: young leaves and shoots are cooked as a leafy vegetable in the East African countries of Kenya and Tanzania. Slenderleaf can be boiled or fried, or used as a potherb in stews and soups (Abukutsa-Onyango, 2004). Elderly people like its bitterness but younger people prefer Crotalaria ochroleuca (rattlepod), a closely related species (Abukutsa-Onyango, 2004). Slenderleaf seeds can be used to produce a hydrophilic polysaccharide with thickening and sizing properties that compare with those of guar gum (Tookey et al., 1963).
Information on the use of Crotalaria brevidens as forage is scarce and most of it come from a series of evaluations carried out on Crotalaria species in Florida in the 1930s. Those evaluations concluded that slenderleaf was the best Crotalaria species for livestock though its palatability and nutritional value were not high (Neal et al., 1935; Ritchey et al., 1941). Slenderleaf was used in its native range in Africa for fodder at least until the 1960s (Dougall et al., 1966), and was part of a series of evaluations planned in Tanzania in the 1980s (Myoya et al., 1988). More recent data remain elusive and it is not known if slenderleaf is currently used for livestock.