Gymnema sylvestre (Retz.) R.Br. ex Sm.

Apocynaceae (part 2), David Goyder, Timothy Harris, Siro Masinde, Ulrich Meve, Johan Venter. Flora of Tropical East Africa, 2012

Morphology General Habit

Scandent shrub or woody twiner with white latex.

Morphology Stem

Stems to ± 5 m long, young shoots shortly villous with white or tawny hairs, older stems lenticellate, to ± 2.5 cm in diameter at base, arising from a long taproot 0.5–1.5(–2) cm long.

Morphology Leaves Leaf lamina

Lamina broadly ovate, obovate, elliptic or suborbicular, 3–7 × 1.5–5 cm, apex acute, shortly attenuate or narrowing abruptly into a short acumen, base rounded or very weakly cordate, pubescent on both surfaces

Morphology Leaves

Leaves opposite, petiole

Morphology Reproductive morphology Inflorescences

Inflorescences extra-axillary, single or paired, much shorter than the adjacent leaves, forming dense subumbelliform clusters of flowers.

Morphology Reproductive morphology Inflorescences Peduncles

Peduncles (0.3–)0.5–1.5 cm long, densely pubescent.

Morphology Reproductive morphology Flowers Pedicel

Pedicels 2–5 mm long, pubescent

Morphology Reproductive morphology Flowers Calyx

Sepals lanceolate to broadly ovate or orbicular, 1–2 × 0.5–1 mm, apex rounded, pubescent with ciliate margins.

Morphology Reproductive morphology Flowers Corolla

Corolla yellow, orange or cream, glabrous except on the corona; tube 1–1.5 mm long, ± completely enclosing the gynostegium; lobes spreading, oblong or triangular with a rounded or somewhat truncate apex, ± 1.5 × 1 mm, margins ciliate

Morphology Reproductive morphology Flowers Corona

Corolline corona forming five fleshy ridges running from the corolla lobe sinus down the length of the corolla tube, pubescent along the lateral faces, frequently bifid and projecting somewhat at the mouth of the corolla tube

Morphology Reproductive morphology Flowers Androecium Stamens

Staminal corona absent

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anther wings ± 0.8 mm long

Morphology Reproductive morphology Flowers Pollinarium

Pollinaria minute, corpusculum ovoid, 0.1 mm long; translator arms slender, ± 0.1 mm long.

Morphology Reproductive morphology Flowers Pollinia

Pollinia ovoid, ± 0.1 mm long

Morphology Reproductive morphology Flowers Gynoecium Style

Stylar head projecting for ± 1 mm beyond anthers, ovoidconical

Morphology Reproductive morphology Fruits

Follicles single, fusiform, 5–9 × ± 0.7 cm, slender, tapering gently into a long attenuate tip, smooth, glabrous

Morphology Reproductive morphology Seeds

Seeds flattened, ± 9 × 5 mm, oblong with a narrow margin; coma ± 3.5 cm long

Figures

Fig 58/5, p 192

Ecology

Riverine forest margins, thicket and dry bushland, frequently on sand; 700–1500 m

Distribution

Flora districts: U1 U2 U3 U4 K4 K5 K7 T1 T3 T4 T5 T6 T7 Z Range: Widely distributed across Old World tropics - in Africa from the northeastern provinces of South Africa northwards to Senegal and Mauritania in the west and Ethiopia in the east, then via the Arabian Peninsula to the Indian subcontinent.

Goyder, D. J., Gilbert, M. G. & Venter, H. J. T. (2020). Apocynaceae (part 2). In: M. A. García (ed.), Flora Zambesiaca, Vol. 7(3). Royal Botanic Gardens, Kew.

Type

Koenig 6733 (LD lectotype), designated by Forster in Austrobaileya 3: 126 (1989).

Morphology General Habit

Scandent shrub or woody twiner with white latex; stems to c.5 m long, young shoots villous with white or tawny hairs, older stems lenticellate, to c.2.5 cm in diam. at base, arising from a long taproot

Morphology Leaves

Leaves opposite, petiole 0.5–1.5(2) cm long; lamina 3–7 × 1.5–5 cm, broadly ovate, obovate, elliptic or suborbicular, apex acute, shortly attenuate or narrowing abruptly into a short acumen, base rounded or very weakly cordate, pubescent on both surfaces

Morphology Reproductive morphology Inflorescences

Inflorescences extra-axillary, single or paired, much shorter than the adjacent leaves, forming dense subumbelliform clusters of flowers; peduncles (0.3)0.5–1.5 cm long, densely pubescent; pedicels 2–5 mm long, pubescent

Morphology Reproductive morphology Flowers Calyx

Sepals 1–2 × 0.5–1 mm, lanceolate to broadly ovate or orbicular, apex rounded, pubescent with ciliate margins

Morphology Reproductive morphology Flowers Corolla

Corolla yellow, orange or cream, glabrous except on the corona; tube 1–1.5 mm long, ± completely enclosing the gynostegium; lobes spreading, c.1.5 × 1 mm, oblong or triangular with a rounded or somewhat truncate apex, margins ciliate

Morphology Reproductive morphology Flowers Corona

Corolline corona forming five fleshy ridges running from the corolla lobe sinus down the length of the corolla tube, pubescent along the lateral faces, frequently bifid and projecting somewhat at the mouth of the corolla tube

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Staminal corona absent

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anther wings c.0.8 mm long

Morphology Reproductive morphology Flowers Pollinarium

Pollinaria minute, corpusculum 0.1 mm long, ovoid; translator arms slender, c.0.1 mm long; pollinia c.0.1 mm long, ovoid

Morphology Reproductive morphology Flowers Gynoecium Style

Stylar head projecting for c.1 mm beyond anthers, ovoid-conical-Follicles single, 5–9 × c.0.7 cm, slender, fusiform, tapering gently into a long attenuate tip, smooth, glabrous

Morphology Reproductive morphology Seeds

Seeds flattened, c.9 × 5 mm, oblong with a narrow margin; coma c.3.5 cm long.

Distribution

Caprivi, Botswana, Zambia, Zimbabwe, Malawi, Mozambique. Widely distributed across Old World tropics - in Africa from the northeastern provinces of South Africa northwards to Senegal and Mauritania in the west and Ethiopia in the east, then via the Arabian Peninsula to the Indian subcontinent.

Ecology

Riverine forest margins, thicket and dry bushland, frequently on sand or stony soil; 100–1200 m.

Recognition

Easily confused with the more southerly Marsdeniadregea, if can be distinguised by the pubescent rather than glabrous leaves, the smooth, unwinged follicles, and the position of the corona lobes which arise from the corolla lobe sinus rather than the gynostegium.