Prota 16: Fibres/Plantes ΰ fibres
Bot. Jahrb. Syst. 19: 265 (1894).
Lasiosiphon glaucus Fresen. (1838), Gnidia eriocephala Meisn. (1841).
Fish-poison bush (En).
Origin and geographic distribution
Gnidia glauca is widely distributed in tropical Africa, from Nigeria eastward to Sudan and Ethiopia and southward to Malawi and Zambia. It also occurs in southern India and in Sri Lanka.
Fibre from the bark is made into rope and thread. The bark is used for lighting fire. A decoction of the boiled root is drunk in East Africa for treatment of indigestion. In Ethiopia root powder mixed with skimmed milk is taken orally for seven days for treatment of rabies. The bark is made into arrow poison in Kenya: it is boiled in water for several hours and the residue is smeared on arrow tips. In India the bark and leaf are used for treatment of blisters, swellings and contusions, leaf extracts are used as insecticide and the stem, bark and leaf as a fish poison. In Sri Lanka the ground whole plant is used as an insecticide and piscicide.
The bark fibre is strong and said to be poisonous. An alcohol extract of the root showed strong in-vivo inhibitory activity against P-388 leukaemia in mice. Extracts of the fresh bark exhibited larvicidal activity against Aedes aegypti. Leaf extracts exhibited some insecticidal activity against Aedes aegypti, Anopheles stephensi, Culex pipiens pallens, Culex quinquefasciatus, Plutella xylostella and Spodoptera litura, and fungicidal activity against Venturia inaequalis. Aqueous extracts of the leaf showed some antifeedant activity against the armyworm Helicoverpa armigera. In Sri Lanka the leaf and twig were found to contain alkaloids.
Large, much-branched shrub up to 6 m tall or small tree up to 15(24) m tall; outer bark grey, brown or blackish, smooth to wrinkled; inner bark fibrous, pale yellow, fragrant. Leaves alternate, clustered in the upper parts of branches, simple and entire, almost sessile or with petiole 13 mm long; stipules absent; blade narrowly elliptical to obovate, (20)2565(85) mm Χ 626 mm, gradually narrowed to the base, rigid, hairy or glabrous, glaucous, midvein prominent beneath. Inflorescence a dense terminal head 25 cm in diameter, 2070-flowered; peduncle widening towards the top, hairy; bracts 612(15), elliptical to ovate, 1015 mm Χ 410 mm, slightly leathery, softly hairy on both sides, cream-coloured or salmon-pink, persistent. Flowers bisexual, regular, (4)5-merous, orange or golden yellow, fading to brown; pedicel 12.5 mm long, hairy; calyx tube cylindrical, 914 mm long, without articulation, the upper part softly hairy, the lower part with dense tufts of silky hairs 24 mm long, lobes imbricate, ovate, entire or lobed, 2.55 mm Χ 1.52 mm, hairy outside; petals inserted in the throat of the calyx tube, elliptical or spathulate, 12 mm long, entire, emarginate or lobed, membranous or fleshy; stamens (8)10, in 2 whorls of unequal length, inserted in the throat of the calyx tube, upper whorl slightly exserted; ovary superior, 1-locular, hairy, style filiform, 610 mm long. Fruit enclosed by the persistent base of the calyx tube. Seeds 34 mm Χ 1.52 mm, black.
In Kenya Gnidia glauca flowers in FebruaryMarch and MayJuly.
Gnidia comprises about 140 species, mainly distributed in tropical Africa, with 20 species endemic to Madagascar, but it also extends into Arabia, western India and Sri Lanka. Gnidia glauca var. glauca is distributed in tropical Africa and southern India, whereas Gnidia glauca var. insularis (Gardner) C.C.Towns. is endemic to Sri Lanka. The latter has twigs and leaves more or less densely covered with persistent long appressed hairs, whereas those of the former are glabrescent.
Gnidia glauca occurs at 9503300 m altitude, in forest margins and associated bushland or wooded grassland, on rocky grassy slopes and around stream beds. In East Africa it is sometimes locally dominant in secondary forest.
Genetic resources and breeding
In view of its wide distribution and local abundance, Gnidia glauca is not threatened by genetic erosion.
Gnidia glauca yields a strong fibre suitable for cordage, but detailed information on the fibre properties is unavailable, making it difficult to assess its prospects. The plant has toxic properties and is used as an insecticide and piscicide. Research on its phytochemistry and the risks of its use for human health and the environment seems warranted.
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Correct citation of this article:
Brink, M., 2009. Gnidia glauca (Fresen.) Gilg. In: Brink, M. & Achigan-Dako, E.G. (Editors). Prota 16: Fibres/Plantes ΰ fibres. [CD-Rom]. PROTA, Wageningen, Netherlands.