Senna hirsuta (L.) Irwin & Barneby

Erect or diffuse, simple or several-stemmed herb, up to 2.5 m tall, becoming softwoody with age, with a fetid smell, hairy but highly diverse in pubescence; twigs grooved and ribbed, densely hairy. Leaves simply paripinnate, 10-20 cm long; stipules linear-acute, 3-15 mm long, usually not persisting; petiole stout, up to 6.5 cm long, villose, above the insertion with a sessile, oblong gland; rachis 3-16 cm long, glandless; petiolules up to 3.5 mm long, slender, villose, often not quite opposite; leaflets 2-8 pairs, strongly accrescent distally, chartaceous, lanceolate-acuminate, 2-12.5 cm x 1-5 cm, 2-6 times as long as wide, slightly unequal-sided, base acute or rounded, dark green, roughly villose on both surfaces. Inflorescence an axillary or rarely terminal, 2-8 flowered raceme (up to 45 in South America), 1(-8) cm long, aggregate in leafy panicles; peduncle up to 3 cm long; bracts linear to lanceolate, 1.5-5 mm long, early caducous; bracteoles absent; pedicel 1-2.5 cm long, pubescent; sepals 5, unequal, 2 outer ones small, orbicular, 4-7 mm long, hairy, 3 inner ones larger, 7-10 mm long, partly glabrous; petals 5, unequal, obovate, 8-28 m long, yellow, glabrous, short-clawed; stamens 10, 2 large with flat filaments 4-7 mm long and curved anthers 7-8 mm long opening by apical pores, 4 smaller and 4 staminodial; ovary woolly, recurved; style short, glabrous with hairy subapical stigma. Fruit a falcate to straight angular pod, 6-28 cm x 3-7 mm, septate, 50-90 seeded, strigose. Seed slightly compressed, orbicular, about 3 mm in diameter, dark olive coloured; areole narrowly elliptical, 0.5-2.5 mm long. S. hirsuta is very variable and 7 varieties have been distinguished for South America. In South-East Asia, 2 varieties occur: var. Hirsuta (widespread as a weed in South East Asia and the rest of the Old World tropics; fruit straight, 11-15 cm x 4-6.5 mm, bristly-hirsute) and var. puberula Irwin & Barneby (widespread in South America, but in South-East Asia only present in the Philippines as a weed, fruit simply arched outward, 15-25 cm x 3-6 mm). The synonymous name Cassia hirsuta is still commonly used in the literature. Until the beginning of the 1980s, Cassia L. was considered to be a genus with over 500 species.

In South-East Asia S. hirsuta flowers throughout the year. The usually numerous fruits are curved when young and straight when mature; They are characterized by somewhat raised, glabrescent sutures and woolly strigose sides.

In South-East Asia S. hirsuta is found in plains and hilly areas. It grows spontaneously in waste locations, along roadsides, railway embankments, dry ditches and in secondary forest. It is found in gardens and fields as a weed and prefers open locations.

S. hirsuta is propagated by seed.

Husbandry: As a green manure S. hirsuta is fast growing, easy to cut, coppices well and can produce considerable amounts of foliage material in a growth cycle of 8 months. Observations in Central Africa indicate that is competes poorly with weeds.

Diseases: S. hirsuta is very susceptible to Corticium salmonicolor and is also affected by a root desease (Rosellina sp.) and by Sclerotium rolfsii.

The weight of 1000 seeds is 4 g.

Shade or shelter: In Africa it is planted as a shade plant in young coffee plantations. Soil improver: As green manure.

Fodder: As forage plant. Food: The leaves and young pods are eaten, usually steamed or cooked in vegetable dishes or in salads. The unpleasant smell can be reduced by relatively long cooking. Medicine: In Java the leaves are used medicinally for treating herpes. A decoction of the leaves is used against irritations of the skin in Thailand. Other products: In Laos the seeds are used as a substitute for coffee.