Crotalaria dombeyana DC.

Crotalaria micans is a shrub up to 4 m tall; young branches angular, appressed pubescent. Leaves trifoliolate; petiole 3-5 cm long, longitudinally grooved above; stipules linear, 0.5-7 mm long, caducous; leaflets oblong-lanceolate to narrowly elliptic, 4-10 cm x 1-4.5 cm, apex acute to acuminate or obtuse, base cuneate, lower surface and midrib above puberulous, upper surface glabrous, lateral leaflets slightly smaller than terminal one. Inflorescence a rather dense, 15-30 flowered, terminal raceme, 15-30 cm long, often leaf opposed; bracts linear, about 1 cm long, very early caducous; pedicel 5-9 mm long; bracteoles similar to bracts but smaller, inserted just above the middle part of the pedicel, flowers bisexual, 5-merous, 12-18 mm long; calyx 8-13 mm long, appressed puberulous, tube campanulate, 5-6 mm long, bilabiate and 5-lobed, lobes longer than the tube, upper lobes triangular-acuminate, often coherent at the tips with the lateral lobes and woolly on the inside of the margins; corolla 14-18 mm long, yellow, purplish-veined. Fruit an inflated, short-stipitate pod, sub-cylindrical, 3-4 cm x 1 cm, appressed puberulous, brown, dehiscent, with 16-20 seeds. Seed unequal-sided heart-shaped, about 4.5 mm x 3.5 mm, fine papillate, yellowish-brown. The genus name ‘Crotalaria’, meaning rattle, is describes the noise made by the seeds shaking in mature pods. The specific epithet means gleaming or with a slight metallic luster.

Flowers bisexual. Seeds mature 7 months after sowing for instance in Indonesia.

C. micans is suited to damp places.

C. micans is a species of savannas and other open places. The shrub tolerates a wide range of climatic and soil conditions. It grows in lowland areas generally and requires full sunlight. In high elevations, seed production is poor.

C. micans originated from central and south America. It has been introduced into many tropical countries, including those in Malesia and Africa where it is locally naturalized.

C. micans is propagated by seed. When broadcast, a seed rate of 20-35 kg/ha is used; 6-12 kg/ha is adequate for sowing rows 0.9-1.5 m apart. In Java it is sown at the onset of the drier season in May-June. In established tea plantations it is sown immediately after pruning.

Early growth of C. micans is fast and can cover soil in 3 weeks after germination and reach 2.5 m after 3 months. It reseeds itself once established. C. micans can be cut repeatedly provided it is not cut too low and a few leaves per stem are left. Yields of 40 t/ha fresh material 4 months after planting have been reported from Java, containing about 150 kg nitrogen.

Fungal diseases caused by Corticium salmonicolor and Sclerotium rolfsii have been reported in Java. It is a host to Lasiodiplodia theobromae affecting both cacao and tea. The Crotalaria bug (Ragmus importunatas) living on the underside of leaves and branch tips causes yellowing of leaves, which can be serious. The dadap fungus (Septobasidium bogoriense) grows on the base of the stem, making it susceptible to other diseases.

There are 55 000 seeds/kg.

Erosion control: The shrub can be grown for erosion control. Nitrogen fixing: C. micans forms root nodules with Bradyrhizobium spp. and fixes nitrogen. Soil improver: The shrub is grown as a green manure and cover crop in plantations of coffee, tea, tobacco and rice. It is easily incorporated into the soil and decomposition is rapid. Ornamental: Characterized by terminal inflorescences on which the large flowers are grouped tightly with prominent, long curled bracts and bracteoles, it is widely grown as an ornamental.

Fodder: Young shoots and leaves are used as fodder for cattle; unlike many other Crotalaria spp., it is reported to be highly palatable and non-toxic. Young vegetative material contains 23% crude protein.