Herbs or small shrubs. Lvs sessile, alternate or the lowest opposite, narrow-linear to triangular or subterete, usually spine-tipped. Fls ☿, axillary, sessile, solitary or in fascicles; bracteoles 2, > perianth. Perianth segments (4)-5, ovate-oblong to ovate-lanceolate, connate only at base, membranous at first, later ± indurate, developing a transverse wing on ridge of back at fruiting. Stamens 5, inserted on an annular disc. Stigmas 2-(3), filiform. Ovary and fr. subglobose. Pericarp membranous or fleshy, surrounded by accrescent perianth, abscissing with perianth. Seed horizontal, with coiled embryo.