Shrubs or small trees, with simple hairs, monoecious. Leaves alternate, often falsely
whorled and then often separated by bare internodes, penninerved or sometimes triplinerved at
base, long or short petioled; stipules short or obsolete. Inflorescences axillary or terminal,
occasionally cauli- or ramiflorous, unisexual or bisexual, variously cymose (often abbreviated
or even reduced to a solitary flower), thyrsiform, racemiform or pseudoracemose, rarely withconspicuous foliaceous bracts. Male flowers: shortly pedicelled; sepals 5, imbricate, sometimes
dorsally gibbous; petals 5, free, exceeding the sepals, mostly brightly coloured; disc glands 5,
often connate; stamens 3 (- 4) or 5 or very rarely 13; filaments connate or rarely somewhat free
or rarely lacking; anthers 2-loculed, extrorse, vertical to horizontal; connectives broad, often
produced and horn-like; pistillode absent. Female flowers: pedicels initially short, gradually
elongating; sepals 5, imbricate, rarely fringed with capitate glands; petals 5, free, coloured as in
males, caducous; disc glands free or united; ovary 3-locular, glabrous or pubescent; each
locule 1-ovuled; styles 3, bifid or occasionally simple or quadrifid, erect or spreading. Fruits
tricoccous capsules, often depressed, smooth or verruculose; seeds trigonous, orbicular or
ovoid; endosperm fleshy; cotyledons flat, broad.
Sri Lanka, S. & NE. India to China and Malesia, ca 90 species; 5 species in India.
Literature.
BALAKRISHNAN, N. P. & T. CHAKRABARTY (1991). A revision of Trigonostemon
Bl. (Euphorbiaceae) for Indian subcontinent. Candollea 46: 601 - 637, ff. 1 - 12.
KEY TO THE SPECIES
1a. Leaves clearly trinerved at base; inflorescences bisexual
4a. Petioles bistipellate at apex with glandular appendages below the lamina on both sides; sepals
often conspicuously dorsally gibbous; anthers sessile with thecae separated from one another
and partially embedded on somewhat triquetrous fleshy coherent connectives, forming a globose
mass as a whole on the receptacle
