Plants annual or perennial. Stem erect, decumbent or prostrate, short or long, branched or not, glabrous or pilose with trichomes white and filamentous. Leaves in a basal rosette, at apex of stem or spirally arranged, linear, capillaceous, linearlanceolate or oblong, densely pilose to glabrous, malpighiaceous trichomes present or not, margins flat to involute, sheath expanded to amplexicaul, persistent or not on the rhizome. Spathes with oblique or lacerate apices. Scapes erect, flexuous or twisted, with 3 ribs, malpighiaceous trichomes present. Capitulum radiate, campanulate, hemispherical or cyathiform, rarely with vegetative proliferation from the centre. Involucral bracts in 5–15 series, the innermost smaller than, equal to or frequently exceeding the flower length by 0.5–7.0 mm; bracts of the outer series of the same colour as the inner series or darker, bracts of the inner series glabrous; floral bracts lacking. Flowers 3-merous, isostemonous, trichomes of the perianth with inner wall smooth. Male flowers actinomorphic, pedicellate, sepals united at the base or up to the middle, concave, hyaline to membranous, glabrous; anthophore present or absent; petals united at the base or up to the middle, hyaline, membranous, glabrous; filaments free from the petals, terete to compressed, anthers dorsifixed, 2-thecous, 4-sporangiate, pistillodes 3, apex papillose. Female flowers slightly zygomorphic, pedicellate or sessile, pedicel elongating or not in fruit, anthophore present or lacking, sepals free, one dorsal sepal which margins are covered by the two ventral sepals, concave, hyaline, membranous, glabrous, petals longer than sepals, narrowly spathulate, connate only in the median region (syngonanthoid fusion), pilose, ciliate or rarely glabrous in the central region, lobes long, concave, each of them enveloping the stigmatic region of each style; styles united up to 0.5 mm, stigmatic and nectariferous portions both insert at apex, stigmatic portion filiform, delicate, stigmas simple, nectariferous portion with papillose apex. Seeds up to 1 mm long, elliptic, testa rugose.