Prota 16: Fibres/Plantes à fibres
Tent. Fl. Abyss. 1: 89 (1847).
Tiliaceae (APG: Malvaceae)
Grewia mollis var. trichocarpa (Hochst. ex A.Rich.) Burret (1910).
Origin and geographic distribution
Grewia trichocarpa is distributed in DR Congo, Rwanda, Burundi, Sudan, Eritrea, Ethiopia, Somalia, Kenya, Uganda and Tanzania. It also occurs in Saudi Arabia and Yemen.
The bark fibre is used for tying, e.g. in hut construction and in basketry. The pounded bark is used for soap-making. The woody branches and wood are used for withies, construction, floors of granaries, tool handles, walking sticks, bows and spear- and arrow-shafts. It is also used as fuelwood. The aerial parts are browsed by livestock and game. The flowers are a source of bee forage. The ripe fruit is eaten.
In African traditional medicine a root decoction is drunk to expel worms and against diarrhoea. A watery extract of the root and that of Grewia tenax (Forssk.) Fiori, is rubbed in to treat skin tuberculosis and other skin ailments. The leaf sap is drunk to treat coughs, colds, abscesses and anaemia. A decoction of the leaf is drunk to expel the placenta, and used as an enema against intestinal parasites. A leaf dressing is applied against furuncles.
Evergreen shrub or small tree up to 6 m tall; crown spreading; branches cylindrical, purplish with pale lenticels, glabrous to hairy in young parts; outer bark smooth, silver-grey to brown, sometimes with vertical bands of brown lenticels. Leaves alternate, simple; stipules subulate, 6–8 mm long; petiole 2–8 mm long, pubescent; blade ovate to elliptical, 1–12(–17) cm × 1–5(–7) cm, base obliquely truncate to rounded, sometimes slightly asymmetric, apex acute to acuminate, margin toothed, 3-veined from the base, glabrous or scattered to sparsely minutely stellate-pubescent above, indumentum beneath variable. Inflorescence a cyme, 1–3 together in a leaf axil, 4–30 mm long, (1–)2–3-flowered; peduncle 4–12 mm long. Flowers bisexual, regular, 5-merous; pedicel 3–12 mm long; sepals elliptical, 6–11 mm long; petals oblong to ovate, 3–7 mm long, notched at the apex, yellow; androgynophore up to 1.5 mm long, glabrous, apex densely hairy; stamens numerous, 4–6 mm long, yellow to orange; ovary superior, 1–2 mm long, densely hairy, style 4–5 mm long, stigma 4-branched. Fruit an unlobed (sometimes 2-lobed) drupe 4–7 mm × 4–7 mm, glabrous or sparsely hairy, yellow to orange; endocarp hard, woody, reticulate.
In Kenya Grewia trichocarpa flowers throughout the year. The ripe fruits are collected in April–June in Tanzania.
Grewia comprises about 150 species, distributed in the tropical and subtropical parts of Africa, Asia and Australia. The bark of Grewia microcarpa K.Schum., a shrub or small tree up to 9 m tall distributed in Kenya, Tanzania, Malawi, Zimbabwe and Mozambique, is locally used as string. In Angola fibre from the bark of Grewia cyclopetala Wawra, a shrub or tree up to 8 m tall, is used for making baskets.
Grewia trichocarpa occurs at (600–)900–2150(–2400) m altitude, on sandy or rocky soils, in wooded grassland, bushland, dry forest and riverine forest. In Tanzania it is common, occurring in areas with an average annual rainfall of 900–1400 mm.
Grewia trichocarpa can be propagated by seed. In Tanzania it is neither planted nor protected by local people. In Uganda it is sometimes considered a weed in plantation forestry.
Genetic resources and breeding
In view of its fairly wide distribution, Grewia trichocarpa seems not threatened by genetic erosion.
Like other Grewia spp., Grewia trichocarpa is a useful multipurpose plant, providing not only fibre, but being a local source of wood, fuel, forage, edible fruits and traditional medicines. Unfortunately, information on properties, such as fibre, wood and fodder quality and medicinal properties, is lacking, making it difficult to assess the prospects for this species.
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Correct citation of this article:
Brink, M., 2009. Grewia trichocarpa Hochst. ex A.Rich. In: Brink, M. & Achigan-Dako, E.G. (Editors). Prota 16: Fibres/Plantes à fibres. [CD-Rom]. PROTA, Wageningen, Netherlands.