Erect, annual, smooth, succulent herb; leaves alternate, attenuate; radical leaves oblong-ovate, broadly acuminate, acute or obtuse, green or tinged with red on veins, glabrous; cauline leaves smaller, lanceolate, passing upward into bracts; petioles deeply channeled; male flowers mostly in long, slender spikes or panicles; perianth 4-5 toothed, green, ovate; stamens 4-5, perigynous, anthers 2-celled, filaments slender; female flowers in axillary, clusters; perianth 3-4 toothed, much enlarged in fruit; ovary ovoid or globose, 1-celled, stigma long, filiform, connate below; fruit urticle, hard, comressed, adnate to perianth, unarmed or with 2-3 spines.