MOLLUGINACEAE (carpetweed family)

Plants annual (perennial elsewhere), not or only slightly succulent, with short taproots, glabrous or with stellate hairs. Stems usually repeatedly dichotomously branched, often slightly thickened at the nodes. Leaves alternate, opposite, or whorled, the leaves at each node usually somewhat unequal in size. Stipules absent. Leaf blades simple, the margins entire. Flowers in small clusters in the leaf axils, sessile or stalked, without bracts, actinomorphic, perfect, hypogynous. Calyx with 5 sepals, these sometimes slightly fused at the base, green or petaloid and white, persistent in fruit. Corolla absent. Stamens 3–10, free or the filaments fused at the very base. Pistil 1 per flower, the ovary superior, consisting of 3(–5) fused carpels, with 3(–5) locules, the placentation axile. Styles absent or very short and as many as the carpels, the stigmas as many as the carpels. Ovules numerous. Fruits capsules (achenes elsewhere), dehiscing longitudinally by 3(–5) valves, not winged at the tip. Seeds minute, somewhat flattened, somewhat kidney-shaped (the embryo appearing curved or coiled) to nearly circular in outline. Thirteen genera, 95–130 species, mostly in tropical and subtropical regions, but especially diverse in southern Africa.

The genera Glinus and Mollugo were treated in the family Aizoaceae by Steyermark (1963) and many earlier authors, but are now considered by nearly all botanists to belong to a group of genera best treated as a separate family, Molluginaceae (Bogle, 1970; Cronquist, 1981, 1991). Aside from differences in flower and fruit morphology (free vs. fused perianth, sepal number, capsule dehiscence), as well as in habit and pubescence types, the two families differ in details of stem anatomy and produce different classes of red pigments (unusual compounds known as betalains in Molluginaceae vs. the more widespread anthocyanins in Aizoaceae).