Heterochiton Graebn. & Mattfeld
Annual or perennial, much branched, prostrate or decumbent, hairy or subglabrous rarely glabrous, mat forming herbs. Leaves opposite, the upper ones often alternate through abortion of one member of a pair, small, sessile or subsessile, entire, obovate to oblanceolate or narrowly elliptic, hairy or sub-glabrous, rarely entirely glabrous; stipules interpetiolar, small, scarious, ovate-triangular with ciliate margins. Inflorescence dense leaf opposed or pseudoaxillary rarely terminal cymose sessile fascicles or clusters. Flowers sessile or subsessile, tetra or pentamerous, perigynous, hairy throughout or subglabrous to glabrous at perigynous zone, hairs straight or uncinate; bracteate, bracts inconspicuous. Sepals 4-5, plano-concave, with or without distinct fimbriate membranous margins, unequal or subequal to equal in length, connivent to erect. Petals 4-5, inconspi¬cuous, subulate-filiform, inserted on rim of cupule, alternate with and shorter than the sepals. Stamens 2-5, antisepalous, inserted on rim of cupule, filaments short, filiform, anthers squarish-oblong or ovoid. Carpels 2, syncarpous; ovary ovoid to sub- globose, glabrous, smooth or papillose in the upper part, membranous, unilocular, ovule 1, basal, amphitropous; style very short, bifid, rarely 2 or absent. Fruit shorter than to slightly exceeding the sepals, 1-celled, 1-seeded, ovoid¬subglobose or ovate-ellipsoid, smooth or papillose in the upper part, membranous, indehiscent utricle enclosed by the persistent calyx. Seed shining dark brown or black, crustaceous, lenticular to ovate-obvoate, smooth; embryo annular, enclosing farinaceous endosperm.
47 species; distributed in Europe, Mediterranean region to montane regions of W. Pakistan, India and North and South Africa.