Habit and leaf form. Shrubs, or herbs (shrublet). Perennial. Leaves cauline. Plants with a basal concentration of leaves (more or less acaulescent), or with neither basal nor terminal concentrations of leaves; rhizomatous (short). Pachycaul. Mesophytic, or xerophytic. Leaves small to large; alternate; distichous; leathery, or modified into spines, or ‘herbaceous’; sessile; sheathing. Leaf sheaths not tubular; with free margins. Leaves simple. Leaf blades entire; acicular, or linear; linear; parallel-veined; without cross-venules; closely sheathing stem and imbricate. Leaves without stipules. Leaf blade margins scabrid or almost smooth. Vegetative anatomy. Plants without silica bodies. Leaf anatomy. Extra-floral nectaries absent.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes, or in panicles, or in racemes. Inflorescences scapiflorous, or not scapiflorous; terminal (to short branches), or axillary (in upper axils); cymose clusters or racemes. Flowers pedicellate (nearly sessile); bracteate; ebracteolate; small; regular; 3 merous; cyclic; pentacyclic. Perigone tube present, or absent. Free hypanthium short tube. Perianth of ‘tepals’; 6; 2 -whorled; isomerous; petaloid; similar in the two whorls, or different in the two whorls; white (whitish), or pink (inner segments); fleshy, or non-fleshy. Androecial members definite in number. Androecium 6. Androecial members adnate; all equal; coherent (connate at the base); 2 -whorled. Androecium exclusively of fertile stamens. Stamens 6 (in 2 whorls); all more or less similar in shape; diplostemonous; inner 3 attached to the perianth for a short distance, outer 3 free from the perianth. Anthers dorsifixed; versatile; dehiscing via longitudinal slits; introrse. Pollen shed as single grains. Gynoecium 3 carpelled. The pistil 3 celled. Carpels isomerous with the perianth. Gynoecium syncarpous; eu-syncarpous; inferior. Ovary plurilocular; 3 locular. Gynoecium stylate. Styles 1; attenuate from the ovary, or from a depression at the top of the ovary; apical. Stigmas 1; 1 - lobed, or 3 - lobed. Placentation axile. Ovules 1 per locule; non-arillate; anatropous to campylotropous.
Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule. Capsules loculicidal. Fruit 3 celled; 1–3 seeded. Seeds endospermic. Embryo well differentiated. Testa without phytomelan.
Additional characters Pollen grains sulculate.