| General Information |
|
| Distribution | A genus of about 20 species, extending from the east African coast across the Indian Ocean to the Indian subcontinent, Malesia, northern and eastern Australia, and north to China and Japan, and across
the southern Pacific to Fiji.
|
|
|
|
Habit
|
Perennial herbs or low shrubs, sometimes scandent or prostrate and rooting at nodes, rarely annual.
|
Leaves
|
Leaves opposite, usually petiolate; blade lanceolate to ovate, rarely ternately compound, pinnatisect or pinnatifid, triplinerved, usually dentate.
|
Flowers
|
Heads terminal, solitary or few, in open dichasial cymes, often on long peduncles, radiate; involucres hemispherical to campanulate, involucral bracts in 2 series; receptacles convex, paleate, paleae oblong, membranous and strongly striate basally; tips thickened, green, blunt or almost so, inner ones inflexed and ± hooded over the maturing achenes, abaxially densely scabrous. Ray florets pistillate and fertile, corollas yellow, lamina shortly 2-(3-)-lobed; disk florets bisexual, corollas yellow or greenish yellow, 5-lobed, without fibers embedding the vascular strands, anther thecae black (rarely dark brown), anther appendages yellow.
|
Fruit
|
Ray achenes cuneiform, 3-angled, with truncate shortly hairy apices, sometimes shortly winged on angles. Disc achenes similar, but 4-angled. Elaiosomes absent. Pappus usually ± absent (represented sometimes by a ring of very short hairs or tiny scales), sometimes with 1–6 weak, fragile awns.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Contributor
|
Nancy Khan
|
