Annual or perennial herbs, usually with short stems. Leaves narrow, spirally arranged in a crowded basal rosette (rarely (setaceum) borne on elongated stems). Inflorescence capitate, white, dirty grey, brown or black. Capitula of many small unisexual flowers on a central receptacle, surrounded by 1-several whorls of involucral bracts; each flower often subtended by a floral bract. Flowers (2-)3-merous, ± actinomorphic to strongly zygomorphic. Perianth usually composed of 2 distinct whorls; calyx of free to almost connate sepals, sometimes spathe-like especially in male flowers. Petals free or partly connate, often with a subapical black gland. Male flowers: stamens as many as or twice the number of sepals. Female flowers: ovary 2-3-locular, superior; style branched. Fruit a loculicidally dehiscent capsule; each loculus 1-seeded. Worldwide: 9 genera and 1100 species, mostly in tropical and warm parts of the world (especially America) but also with a few temperate species. Zimbabwe: 3 genera and 26 taxa. |
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