Corolla white, pinkish or crimson, tube (3)4–8 mm. long, filiform, glabrous, lobes 3–5.5 x 0.8–1 mm., lanceolate, often a little hairy near apex; filaments 3–5 mm. long, with long white hairs near base, anthers 0.8–1.2 mm. long; style 7–10 mm. long, stigma lobes c. 1 mm. long; ovary 1–1.5 x 1 mm., mostly rather densely hairy.
Leaves decussate, pseudo-verticillate; blades (10)15–60 x (1)2–10(12) mm., lanceolate, linear-lanceolate or linear, less commonly ovate-lanceolate, glabrous or a little hairy on margins and midvein above; petioles (sub)obsolete; stipular sheath with 1–5 filiform setae, 1–3(4) mm. long.
Inflorescence many-flowered, head-like or subcylindrical and to c. 20 mm. long when in flower, often somewhat elongated and more spike-like when in fruit.
Calyx: enlarged, foliaceous lobe c. 3–6(8) x 0.5–1(2) mm., linear-lanceolate, glabrous or hairy on margins, setiform lobes minute, hairy.
Seed brownish, c. 2–2.5(3) x 0.6–0.8 mm., oblong, dorsal side convex, somewhat keeled, ventral side ± flat.
Stems 15–100 cm. long, branched or sometimes unbranched, with 2 rows of hairs above, glabrescent below.
Perennial herb or subshrub with a woody base, several-stemmed, erect or straggling.
Bud with limb abruptly expanded into a subcylindrical head.
Fruit yellowish brown; mericarps 2.5–3(4) x 0.7–1 mm.