Leucas volkensii Gürke

Lamiaceae (Labiatae), A.J. Paton, G. Bramley, O. Ryding, R.M. Polhill, Y.B. Harvey, M. Iwarsson, F. Willis, P.B. Phillipson, K. Balkwill, C.W. Lukhoba, D.F. Otieno, & R.M. Harley. Leucas, G. Bramley. Flora of Tropical East Africa. 2009

Type

Type: Tanzania, Kilimanjaro, above Marangu, 2700 m, Volkens 1140 (B†, holo.; BM!, BR, K!, iso.)

Morphology General Habit

Erect herb or shrub with branching stems, 1–3 m high, often from a woody rootstock

Morphology Stem

Stems pubescent with upward or downward-pointing hairs, becoming less pubescent and woody

Morphology Leaves

Leaves petiolate; blades lanceolate to narrowly ovate, rarely narrowly elliptic, 8.5–15 × 3.5–7 cm, margins closely serrate, the serrations with tiny mucronate tips, apex acute to acuminate, base rounded then slightly attenuate, upper surface lightly pubescent with appressed short eglandular hairs, lower surface pubescent, sometimes densely so, hairs more plentiful on venation, also with yellow sessile glands; petioles 25–40 mm long, pubescent with closely appressed hairs

Morphology Reproductive morphology Inflorescences

Inflorescence of 4–11 verticils spaced 15–40 mm apart, usually laxly spaced, occasionally becoming more clustered near apex; verticils congested with many flowers; pedicels ± 1 mm; bracteoles lanceolate to subulate, 8–15 mm long, apex spinescent, pubescent , with occasional yellow sessile glands, usually deflexed below the inflorescence

Morphology Reproductive morphology Flowers Calyx

Calyx funnel-shaped, the anterior lip protruding more than the posterior lip at the mouth, 6–8 mm long at anthesis, expanding 1–2 mm in fruit, outer surface pubescent along vein ridges, with yellow sessile glands, inner surface with short hairs; throat somewhat asymmetric, the posterior lip more erect than the anterior lip which protrudes further from the tube; lobes 10, triangular at base then subulate, with short glandular hairs, posterior lip divided into 3 lobes, the centre lobe 3–6 mm, the outer two 1–3 mm, lobes erect, 2 lateral lobes present between the anterior and posterior lips, 1–3 mm long, anterior lip with five lobes, 1–3 mm long

Morphology Reproductive morphology Flowers Corolla

Corolla white, 10–16 mm long; tube 6–8 mm long, lower half more or less glabrous, upper half with appressed hairs, inner surface with patches of short glandular hairs leading to an undulate band of glandular hairs halfway down the tube; posterior lip 4–8 mm long; anterior lip 3–7 mm long, inner surface with patches of minute glandular hairs, outer surface pubescent except on the backs on the lobes

Morphology Reproductive morphology Fruits

Nutlets dark brown, ± 2 × 1.5 mm, gland-dotted, with more distinctive glands and hairs on the flattened top.