© Geoff Nichols

The attractive yellow heads ( Gnidia kraussiana ) is a useful medicinal plant, but can be very poisonous to humans. It can also be very poisonous to foraging animals.

Description
Gnidia kraussiana is a robust small grassland shrublet, up to 0.5 m in height. The stems are erect and hairy, arising from a perennial underground tuber. The small, alternate leaves are lanceolate with pointed tips, covered with silky hairs on both surfaces, with margins often fringed with hairs, 30 mm × 10 mm, and borne on short stalks. Flowers are yellow, tubular, sweetly scented, covered with silky hairs, and borne in dense leafless terminal flowerheads of 18–45 flowers. Gnidia kraussiana flowers throughout the year. It can be confused with G. burchellii, which is a woody shrub with leaves congested towards the ends of branches, and also with G. polycephala, which has numerous, erect leafless branches, and with few-flowered, hairy heads, each with a few large, papery bracts below the flowers.

© Geoff Nichols

Conservation status
According to Raimondo et al. (2009), Gnidia kraussiana is Red Listed as Least Concern (LC), as evaluated against the five IUCN criteria.

Distribution and habitat
Gnidia kraussiana is widely distributed in Africa. In South Africa, it occurs naturally in grassland areas in the eastern and northern parts of the country. It is very prominent in recently burnt grassland. It can often be confused to the closely related species such as G. polycephala, which mainly occurs in Limpopo Province, and G. burchellii, which occurs in most parts of the country except the central interior.

Derivation of name and historical aspects
The genus Gnidia was named after a Greek city, knidos, where a kind of laurel grew. The specific name ‘ kraussiana ' is in honour of Dr F.F. von Kraus (1812–1890), professor at Stuttgart and one of the earliest explorers to travel and collected many plants in South Africa.

Ecology
Little is known about the ecology of this species.

 Uses and cultural aspects
Gnidia species contains high levels of toxic diterpene esters and coumarins. However, their roots are used medicinally for various types of ailments, such as constipation, boils, burns, snakebites, coughs, insanity and poor appetite. The roots of G. polycephala are used for several ailments in Botswana. The leaves of G. capitata and G. gymnostachy are ground to a snuff, smoked or used as a poultice to treat stomach-ache, earache or toothache.

In some parts of Africa, the crushed rhizome of Gnidia kraussiana, mixed with Strophanthus hispidus is used as an effective arrow poison. In Malawi, Zimbabwe, and further north, the plant is utilised as a fish poison. In South Africa, though the plant is well known for its extreme toxicity, its decoctions are used to ease trauma in childbirth. The root of umarhedeni (as the plant is known in Xhosa) is also very effective for the treatment of sexually transmitted infections, known as ukubhajwa. The correct procedure for preparation of this medicine must be strictly adhered to: the boiling decoction of the root must be cooled and reheated ten times before the medicine is ready for use. A cup of the medicine must be filled to the level of the first joint of the index finger (an overdose could be fatal) and is administered as an enema.

In livestock, Gnidia species poisoning result in severe diarrhoea, weakness, fever and a rapidly weakening pulse or even death if large quantities are ingested. In humans, powdered material of Gnidia species causes irritation of the nose and throat, followed by coughing and sneezing, and eventually headache and nausea.

© Geoff Nichols

Growing Gnidia kraussiana

There are no records of Gnidia kraussiana ever being cultivated in gardens.

References and further reading

• Fabian, A. & Germishuizen, G. 1997. Wild flowers of Northern South Africa . Fernwood Press, Cape Town.
• Germishuizen, G. & Clarke, B. 2003. Illustrated Guide to the Wildflowers of Northern South Africa. Briza, Pretoria.
• Raimondo, D., Von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. & Manyama, P.A. (eds). 2009. Red List of South African plants 2009. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
• Van Wyk, A.E. & Malan, S. 1997. Field Guide to the Wild Flowers of the Highveld. Struik, Cape Town.
• Van Wyk, B.-E. & Gericke, N. 2000. People's plants: A guide to useful plants of southern Africa . Briza, Pretoria.
• Van Wyk, B.-E., Van Heerden, F. & Van Oudtshoorn, B. 2002. Poisonous plants of South Africa. Briza, Pretoria.
• Van Wyk, B.-E., Van Oudtshoorn, B. & Gericke, N. 2009. Medicinal plants of South Africa . Briza, Pretoria.
• Zukulu, S., Dold, T., Abbott, T. & Raimondo, D. 2012. Medicinal and charm plants of Pondoland . South African National Biodiversity Institute, Pretoria.