Gomphocarpus semilunatus (PROTA)
Gomphocarpus semilunatus A.Rich
- Protologue: Tent. fl. abyss. 2: 39 (1851).
- Family: Asclepiadaceae (APG: Apocynaceae)
- Asclepias semilunata (A.Rich.) N.E.Br. (1902).
Origin and geographic distribution
Gomphocarpus semilunatus is distributed from Nigeria eastward to Ethiopia and from there southward through East Africa to southern DR Congo, Zambia and Angola.
Fibre from the inner bark of Gomphocarpus semilunatus is used for making fishing nets. After processing, it can be spun with cotton, and it is used to make snares and waistbands. The seed floss is used for stuffing in Uganda.
In traditional medicine in Rwanda a decoction of the whole plant is taken for the treatment of malaria, fever and madness and an extract of the aerial parts is drunk as an aphrodisiac. In Burundi a leaf infusion or juice from the leaves is drunk as an emetic and a leaf decoction is used as wash to serve as a tonic for pregnant women. In Kivu (DR Congo) the whole plant is made into a paste that is rubbed on rheumatic limbs. In Kenya a warm decoction from the roots is drunk to expel intestinal worms and leaves are used as a cure for fever, congested nose and epilepsy. In Uganda the bark is chewed or root preparations are taken to end vomiting, and the whole plant is eaten with groundnut-paste as a cure for hypertension. Drops from crushed leaves are instilled in the nose as a cure for migraine. In veterinary medicine a leaf infusion is instilled to induce uterus contractions in cows.
The bast fibre strands are 1–1.5 m long, white to pale brown, lustrous and fairly strong. They are considered suitable for coarse textiles. The fibre strands are easily broken down (‘cottonized’) into the ultimate fibres, which have about the same length and width as cotton but lack a natural twist, which might cause trouble in spinning with machinery designed for cotton.
Shrubby perennial herb, 1–2.5 m tall, stems stout, erect, frequently unbranched, densely hairy with spreading white hairs in the upper part, woody at base, with taproot. Leaves opposite or in whorls of 4, simple and entire; petiole 2–6 mm long; blade linear to narrowly linear-lanceolate, 8–12 cm × 0.5–1.5 cm, base cuneate or truncate, apex acute or attenuate, sparsely hairy with soft white hairs particularly on midrib and margins. Inflorescence an extra-axillary, nodding umbel, 5–9-flowered; peduncle 1–4 cm long; bracts deciduous. Flowers bisexual, regular, 5-merous; pedicel 1.5–2 cm long; sepals lanceolate, 5–9 mm long, attenuate; corolla reflexed, white or pink, lobes ovate, 7–9 mm × 4–5 mm, subacute; corona lobes attached c. 1 mm above base of staminal column, laterally compressed, 3 mm × 2.5–3 mm, shorter than the column; anthers with c. 2 mm long wings; ovary superior, carpels 2, free, stigma head flat. Fruit a pair of upright follicles, each follicle subglobose, 7 cm × 5 cm, not beaked, inflated, balloon-like, with filiform processes c. 1 cm long, many-seeded. Seeds ovate with one convex and one concave face, c. 3.5 mm × c. 1.5 mm, warted, hairs c. 3 cm long.
Other botanical information
Gomphocarpus comprises about 20 species and is distributed in tropical Africa and Peninsular Arabia.
Gomphocarpus physocarpus E.Mey. is native to Mozambique, Botswana, South Africa and Swaziland. It can be distinguished from Gomphocarpus semilunatus by a much shorter calyx and by the shape of the corona. It has been introduced elsewhere and is found in seasonally dry and disturbed areas of Kenya, Uganda, Tanzania and Zambia. In several Indian Ocean islands an introduced Gomphocarpus species, probably Gomphocarpus physocarpus, is used medicinally. In Australia the species hybridizes with Gomphocarpus fruticosus (L.) W.Aiton and hybridization is probably taking place in East Africa as well. In South Africa the powdered leaves are sniffed as a cure for headache, tuberculosis and as an emetic. The latex is applied to warts. The fibre use that has been reported for the species should be attributed to Gomphocarpus semilunatus.
Gomphocarpus semilunatus occurs at 300–2600 m altitude in seasonally flooded grasslands and waste places, frequently in large numbers.
In Rwanda in the 1950s the stems of plants collected from the wild yielded 0.7% fibre after 10 days of retting. Gomphocarpus semilunatus has been cultivated in East Africa, where it proved very susceptible to insect pests. Fibre yields in East Africa have been estimated at 280–400 kg/ha.
Gomphocarpus semilunatus is widespread and not heavily exploited so no threats are foreseen.
The properties of the fibre produced by Gomphocarpus semilunatus is such that it could be used to produce soft fabrics. As a first step to verify the feasibility of commercial exploitation, research into domestication and management are needed.
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- C.H. Bosch, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Correct citation of this article
Bosch, C.H., 2011. Gomphocarpus semilunatus A.Rich. In: Brink, M. & Achigan-Dako, E.G. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Accessed 7 March 2020.
- See the Prota4U database.