Hygrophila mutica (C.B.Clarke) Vollesen

J. R. Timberlake, E. S. Martins (2013). Flora Zambesiaca, Vol 8 (5) Acanthaceae Part 1. Royal Botanic Gardens, Kew

Type

Zimbabwe, ‘South African Goldfields’, 1870, Baines s.n. (K holotype).

Morphology General Habit

Erect or ascending perennial herb, often pyrophytic; stems up to 40 cm long, usually 2–10 cm when pyrophytic, quadrangular, glabrous

Morphology Leaves

Leaves hirsute-strigose on edges and midrib with long flattened white hairs; lamina linear to lanceolate or oblanceolate, largest 1.5–5.2 × 0.1–0.5 cm; apex subacute to rounded; base truncate

Morphology Reproductive morphology Inflorescences

Inflorescence spiciform to paniculate, up to 15 cm long; axis glabrous apart from a line of hairs at nodes; flowers all solitary or in 2(5)-flowered sessile clusters basally; bracts to 1.5 cm long, lanceolate; pedicels 0.5–2 mm long

Morphology Reproductive morphology Flowers Calyx

Calyx 11–20 mm long of which fused basal part is 4–6 mm, glabrous at base and with hirsute-ciliate lobes; ventral and lateral lobes lanceolate, dorsal slightly wider, 2–5 mm longer than others

Morphology Reproductive morphology Flowers Corolla

Corolla mauve to purple, rugula white with purple veins, orange spots absent or faintly defined, 25–33 mm long of which linear tube 9–12 mm, expanded tube 5–9 mm and limb 11–13 mm, sparsely puberulent; dorsal lip oblong, lobes 3–4 mm long, broadly rounded; ventral lip with scattered long tapering hairs, broadly obovate, lobes 6–8 mm long, broadly rounded

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens included in expanded part of tube; filaments glabrous, dorsal 3–5 mm long, ventral 5–8 mm; anthers 1.5–2 mm long; style with scattered hairs, stigmatic lobe c.1 mm long, slightly flattened

Morphology Reproductive morphology Fruits

Capsule 10–11 mm long, with a few capitate glands near apex, otherwise glabrous, with 8 seeds per locule

Morphology Reproductive morphology Seeds

Seeds mm long.

Distribution

Zimbabwe. Not known elsewhere.

Ecology

On cracking clay in seasonally inundated pans and vleis, often subject to burning; 1300–1500 m.

Conservation

Endemic to the central watershed in Zimbabwe; possibly Near Threatened as habitat under threat.