Jatropha curcas L.: a potential biodiesel crop for Sri Lanka

Jatropha curcas is a perennial, monoecious shrub or small tree up to 6 m high; bark pale brown, papery, peeling; slash exudes a copious watery latex, soapy to tough but soon becoming brittle and brownish when dry; branches glabrous, ascending, stout. Leaves alternate, palmate, petiolate, stipulate; stipules minute; petiole 2-20 cm long, blade 3-5 lobed, 12.5-18 x 11-16 cm, lobes acute or shortly acuminate at the apex, margins entire or undulating, leaf base deeply cordate, glabrous or pubescent only on the veins below, basal veins 7-9, prominent, venation reticulate. Inflorescence a cyme formed terminally on branches and complex, possessing main and co-florescences with paracladia. The plant is monoecious and flowers are unisexual; occasionally hermaphroditic flowers occur; 10 stamens arranged in 2 distinct whorls of 5 each in a single column in the androecium and in close proximity to each other. In the gynaecium, the 3 slender styles are connate to about 2/3 of their length, dilating to a massive bifurcate stigma. Female flowers with sepals up to 18 mm long, persistent; ovary 3-locular, ellipsoid, 1.5-2 mm in diameter, style bifid. Fruit an ellipsoid capsule 2.5-3 cm long, 2-3 cm in diameter, yellow, turning black. Seeds black, 2 per cell, ellipsoid, triangular-convex, 1.5-2 x 1-1.1 cm. The meaning of the specific name ‘curcas’ is not known. It was first given 400 years ago to ‘certain seeds’ by the Portuguese doctor Garcia de Orto, who published a work on Indian medicinal and drug plants in 1563.