Annuals, dwarf shrubs, shrubs rarely small trees. Glabrous or with very diverse types of indumentum. Young stems whitish, purplish or fresh green with pale longitudinal lines. Leaves alternate, sometimes subopposite or opposite, rarely distichous; usually semiterete or terete and ± succulent, more or less linear, eventually with a spiny apex, isolateral, mostly with 1 large central bundle and numerous smaller peripheral bundles near to the Kranz layer, usually short-lived and functionally replaced in flowering time by bracts and bracteoles; leaf base very variable in shape. Bracts more or less leaf-like and succesively shorter. Bracteoles 2, green at least in upper part, usually much shorter and more uniform in length, enclosing at least the lower 2/3 of the flowers. Flowers sessile, solitary or clustered, in simple or paniculate spikes; usually bisexual, protandrous, anemophilous or/and entomophilous. Tepals 5, free from base, 1-4 mm long, varying in outline from circular to narrow ovate and from very thin and delicate to moderately thickened or stiff and coriaceous, with or without a distinct green blotch on back, the outer wider than the inner, with 1 to several veines, in lower 1/2 usually with a distinct transverse line associated with the later formation of a wing-like outgrowth. Stamens 5, antitepalous, anthers with thecae more or less deeply divided from base, apically with an appendage of very different size and shape; filaments band-shaped, mostly inserted on the outside of a glandular, lobed interstaminal disc, more rarely disc absent. Ovary globular, ovoid or depressed, style shorter or longer, rarely absent; stigmas 2, rarely 3, spreading, recurved or revolute, flat, papillose on upper side only (in our species); ovule 1, basal. Fruit usually made up of an utricle with adnate fruiting perianth, both shed together as an anemophilous diaspore; utricle commonly enclosed, sometimes exposed on upper side. Tepals in fruit with 5 subequal wings or the 2 inner much smaller, wings horizontally spreading, flat or somewhat flexuose, often partly overlapping, very thin and translucent with delicate radial veins, or thicker, coriaceous, and then pale or brown, when young and fresh often purple, pinkish, orange or yellow; tepal back above the wings often variously enlarged and thickened, usually connivent, the lobe apices often forming very typical dome-, cone- or column-like structures; tepals below the wings slightly to moderately hardened, rarely indurated, forming a bowl- or cup-like structure, its base usually flattened, with 5 shallow grooves and a polygonal rim surrounding the central scar, more rarely the base rounded; sometimes 1 or 2-3 fruits on condensed lateral spikes forming wingless complex fruits by their greatly enlarged, fused and indurated bracts and bracteoles. Utricle drum-, disc-or pot-shaped, or semiglobular with the upper side flattened; pericarp membranous. Seed horizontal, more rarely oblique or vertical, with membranous testa; endosperm almost absent; embryo flat to conical spiral or helical, greenish.