Source:
SSA
Description:
Annual or perennial herbs, sometimes woody at base, sometimes decumbent. Leaves opposite, entire, petiolate, sessile or subsessile, usually pubescent. Inflorescences terminal on stem and branches, spiciform or capitate, bracteate, ultimate division basically a triad of 1 central bisexual fertile and 2 modified sterile flowers formed of uncinate, straight or glochidiate spines or bracteoliform processes; bracts ovate, usually aristate, accompanied by 2 bracteoles, persistent, finally +/- deflexed; bracteoles and perianth, all or part, falling as a burr in fruit. Tepals 5, free, subequal, very shortly mucronate or some hooked-aristate, often pilose. Stamens 5, shortly monadelphous at base; filaments linear, alternating with fringed pseudostaminodes; anthers 2-thecous. Ovary obovoid; ovule solitary, suspended from an elongated, basal funicle; style slender; stigma capitate. Capsule thin-walled, indehiscent, closely held in perianth. Seed ovoid, slightly compressed; perisperm/ endosperm copious. x= 17 (7, 8) (polyploidy) .
Distribution:
Species +/- 25, tropics of both Old and New World; mostly Africa; 6 in sthn Afr., widespread, but less so in the Cape region.
Classification:
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