Herbs or shrubs, erect, ascending or procumbent with slender or stout and succulent
stems and fibrous or stout rootstock. Leaves simple, opposite, dentate or entire. Heads
radiate, heterogamous, solitary, terminal or on peduncles among the upper branches.
Involucre campanulate; bracts 1 - 2 seriate; outer herbaceous; inner ones membranous.
Receptacle flat or slightly convex. Ray florets several, female; corolla yellow or white,
entire to 2 - 3 dentate. Ovary compressed; style branches slender, elongte, curved. Disc
florets yellow, numerous, bisexual or rarely male, tubular-campanulate, 5-lobed. Anther
bases sagittate; apical appendage ovate. Style arms broad, acute or obtuse. Achenes of
the ray and disc florets cuneate-obovate, triquetrous or laterally compressed, truncate or
rounded at the apex. Pappus cup like or of 1 - 2 weak awns or absent.
In tropical and warm temperate regions of the world; ca 70 species 5 in India.
KEY TO THE SPECIES
1a. Involucral bracts nearly equalling the disc florets
2
b. Involucral bracts much longer than the disc florets