Source:
SSA
Description:
Annual herbs. Leaves opposite, sessile or with 2 +/- widened and clasping petioles, lobed or 1-3-pinnatisect. Capitula radiate, solitary on terminal and lateral branches, long-peduncled. Involucre subhemispheric; bracts in 2 rows, connate basally, membranous. Receptacle flat. Ray florets neuter; corolla white, pink, lilac or orange, strap-shaped, entire or subdentate. Disc florets many, bisexual, fertile; corolla yellowish, cylindric but widening slightly near apex, equally 5-toothed terminally. Style with branches slender, thickened above, hirtellous, tipped with short and acute appendages. Stamens with hirsute filaments. Cypselas linear, +/- fusiform-tetragonal, usually compressed, apically usually attenuate into beak. Pappus of 2-4(-8) barbellate or scabrid awns. x = 12 (11, 13, 17) (aneuploids, polyploidy, B-chromosomes).
Distribution:
Species 26, in tropical and warm regions of America, especially Mexico; 2 weeds in sthn Afr.: *Cosmos bipinnatus Cav. known from the Northern Province, North-West, Gauteng, Mpumalanga, Free State and Lesotho, and *C. sulphureus Cav. from KwaZulu-Natal.
Classification:
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