Annual herb. Branches glabrous below, puberulous above. Leaves opposite or whorled, stipulate, fleshy, linear to spathulate, up to 30 mm long. Inflorescence 3-flowered dichasial cyme borne on prominent, broad, flattened peduncles, the latter becoming wing-like or broad leaf-like in fruit and falling off with the fruiting cymes. Of each 3-flowered cluster, the middle flower is fertile, symmetrical, the laterals usually sterile and assymetrical and spinescent in fruit; also on either side accompanied by short sterile branches with recurved spines; some of the bracts enlarging in fruit to broadly spathulate, with a long cusp and often pinkish in colour. Sepals of the fertile flower 4, oblong-linear, hooded, unequal, keeled, the inner 2 membranous. Fruit a membranous, hyaline utricle with a compressed seed.