Prota 16: Fibres/Plantes à fibres
Sitzungsber. Ges. Naturf. Freunde Berlin 1864: 1 (1864).
Pouzolzia hypoleuca Wedd. (1869), Pouzolzia baronii Leandri (1951).
Soap nettle, snuggle-leaf, soap bush (En). Chopo (Sw).
Origin and geographic distribution
Pouzolzia mixta is distributed from Sudan and Ethiopia southward through Tanzania, Malawi, Zambia and Angola to Namibia, Botswana, Zimbabwe, Mozambique, South Africa and Swaziland. It also occurs in Madagascar and in Yemen. The distribution shows a particular disjunction, as it is absent from Kenya and probably from Uganda as well.
Fibre from the bark is used for rope and string. It was formerly much used for fishing nets in Malawi, before nylon nets became popular. Thin strips of bark fibre have been used to stitch wounds in Zimbabwe, and are thought to have healing effects. The leaf is cooked as a vegetable often together with that of Obetia tenax (N.E.Br.) Friis. The crushed leaf is used as a substitute for soap to wash hands and clothes. Children use the leaves, which can be made to stick together, to fashion cups, baskets and hats. Furthermore, the plant is used as an ornamental, and is a source of bee forage.
Pouzolzia mixta finds wide application in African traditional medicine. A root extract or root decoction is taken for the treatment of diarrhoea and dysentery. An infusion of the root is drunk to treat constipation, venereal diseases and female sterility, and as an aphrodisiac and contraceptive. Root powder is inserted into the vagina against female sterility and to prevent abortion. A root infusion is instilled into the vagina to dilate the birth canal during labour. A maceration of the root and leaves is drunk to expel the placenta after childbirth, or an infusion of the root or bark is instilled into the vagina for this purpose. The powdered root is taken in porridge against uterine pain. A paste of the root is applied on burns and a depressed fontanel. A decoction of the stem is administered as an enema for the relief of biliousness. The pounded leaf is mixed with water to form a drink taken for treatment of measles.
The ultimate fibres of material from Malawi were (6–)11(–26) mm long and (23–)30(–40) μm wide. The fibre contained 66.7% cellulose. The stem contains a high amount of gums, like that of ramie, making degumming of the fibre necessary. Experiments showed that the fibre can be degummed fairly easily. Reports on the strength of the fibre are inconsistent. The wood is soft.
Deciduous shrub or small tree up to 3(–)5 m tall, devoid of stinging hairs; stems juicy, with wide spongy pith or hollow centre; outer bark longitudinally striate, greyish or reddish brown, with prominent scars of leaves and inflorescences; young branches reddish, densely hairy, glabrescent. Leaves alternate, simple; stipules ovate to lanceolate, up to 5 mm long, acute to acuminate at the apex, membranous, red-brown, hairy; petiole 0.5–2(–3) cm long, densely hairy; blade ovate to lanceolate, 2–11.5 cm × 1–7.5 cm, base obliquely cuneate to rounded or truncate, apex attenuate-acute to acuminate, margin entire, upper surface dark green and velvety or rough, with stiff hairs and point-shaped mineral concretions, lower surface arachnoid to white-felted, 3-veined from the base, with 2–3 pairs of lateral veins. Inflorescence an axillary cluster, sessile, male or bisexual with many more male flowers than female ones; bracts narrowly ovate, up to 1 mm long. Flowers unisexual, greenish white; male flowers on pedicel c. 1 mm long, (4–)5-merous, 15–2.5 mm long, tepals densely hairy; female flowers sessile, 1–3 mm long, constricted at the toothed apex, hairy, with 3–8 longitudinal ridges of which 2 usually larger than the rest, ovary superior, enclosed in the perianth, stigma protruding. Fruit a more or less compressed achene 1.5–2.5 mm long, smooth, shiny, white to dark brown, surrounded by the persistent perianth.
In southern Africa Pouzolzia mixta generally flowers in November–December and fruits in December–February.
Pouzolzia comprises 36 species, mainly in the Old World tropics. Pouzolzia denudata De Wild. & T.Durand (synonym: Pouzolzia andongensis Hiern), an annual herb up to 2(–3) m tall distributed from Côte d’Ivoire eastward to Ethiopia and Uganda, and southward to Angola, is recorded to be exploited for its fibre in Angola, but details on this use are lacking. The fibre is white, and the ultimate fibres are 10–20 mm long and (2.5–)13–22(–30) μm wide, with a cell wall thickness of 5.5–6 μm. The bark contains about 15% fibre. In DR Congo the leaf is eaten as a vegetable. The roasted leaf is applied to promote healing of circumcision wounds. Leaf pulp mixed with palm oil is rubbed in for the treatment of goitre. The leaf is used for treatment of eye diseases in dogs.
Pouzolzia mixta occurs in drier areas at 100–1900 m altitude, in wooded grassland, open deciduous woodland, wooded ravines and riverine thickets and forest, usually in rocky locations, sometimes on sand.
Pouzolzia mixta is usually collected from the wild, but in Malawi it has often been planted in fishing villages. It can be propagated by seed.
The traditional method to obtain fibre for fishing nets in Malawi was to scrape off the outer bark, and to dry the remaining stems in the sun. Later they were soaked in water and partially dried, after which the white inner bark fibre could be peeled off easily. The inner bark was dried and separated into narrow strips. String was made by rolling out these strips with the palm of the hand on the thigh. The various lengths were spliced and rolled together into long skeins of string, which varied from fine to thick, according to the intended purpose.
In Tanzania tender leaves to be eaten as a vegetable are collected in the rainy season. They are chopped and cooked with coconut milk or pounded with groundnuts, and served with ugali or rice.
Genetic resources and breeding
As Pouzolzia mixta is widely distributed and locally common, it is not threatened by genetic erosion.
Pouzolzia mixta is a useful local source of fibre for cordage. The absence of stinging hairs gives it an advantage over other Urticaceae. The fibre is much shorter than that of ramie and needs degumming, whereas reports on its strength vary. Therefore, commercial exploitation of this fibre does not seem a viable option. The lack of interest in Pouzolzia mixta and other representatives of the genus from pharmacologists is surprising, as medicinal use is common.
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Correct citation of this article:
Brink, M., 2009. Pouzolzia mixta Solms. In: Brink, M. & Achigan-Dako, E.G. (Editors). Prota 16: Fibres/Plantes à fibres. [CD-Rom]. PROTA, Wageningen, Netherlands.