Scientific name

Datura feroxL.

Synonyms

Datura feroxNees

Common names

Fierce thorn apple, large thorn apple, long spine thorn apple

Family

Solanaceae

Origin

China

Naturalised distribution (global)

Datura ferox is widely naturalised in the tropics and sub-tropics.

Introduced, naturalised or invasive in East Africa

Datura ferox is invasive in parts of Kenya, Tanzania and Uganda.

Habitat

It grows in waste grounds and disturbed agricultural areas. It is often found growing along roadsides, river flats and near stockyards. It prefers warm, temperate and subtropical regions.

Description

Datura ferox is hairless (glabrous) or sparsely hairy (sparsely pubescent) annual herb, with a somewhat dense covering of short, weak, soft hairs) and with non-glandular hairs, that grows up to about 1.5 m high.

The branches are repeatedly forked and green or purplish towards the base. The whole plant is moderately hairy except for the more mature parts, on which the hairs may be sparse or absent.

The mature leaves range from broadly ovate (egg-shaped in outline with broad end at base)and mildly angular to rounded-triangular mostly 8-14 cm long and 6-16 cm wide with a few shallow usually toothed or sinuate (with a deeply wavy margin) lobes. The leaves are alternate and are on long slender stalks. The leaves have an unpleasant odour when crushed.

The flowers are white and are borne singly on short stalks in the forks of the branches. They are trumpet shaped when fully open. The corolla is 4-6cm long, consists of five connate (joined) petals that end in a slender point 1-2mm long. Stamens are not exserted (stamens are not protruding beyond the sepals or petals), and the stigma is below the anthers. The calyx is usually 3.5cm long with the lobes being 4-7mm long.

The fruit is a capsule that is ellipsoid in shape, 2-4cm long and 2-3cm in diameter. There are usually 40-60 spines that are stout, conical, sharp and usually longer towards the apex of the capsule. They are generally 10-15 mm long, with the longest being at least half the length of the capsule. The seeds are 4-5mm long and are either black or grey.

Reproduction and dispersal

Datura ferox reproduces through seed. It can be spread as a contaminant of crop seeds/grains.

Similar species

Datura ferox and Datura stramonium (common thornapple) produce erect capsules on straight stalks which contain black or grey seeds.

Datura leichhardtii, Datura metel, Datura inoxia and Datura wrightii can be differentiated from these two species as their capsules are held on a curved stalk, and they produce brown or yellow seeds.

D. ferox can be distinguished from D. stramonium by its capsule which, has about 40-60 spines of variable length.

D. ferox flower is shorter (4-6 cm long) compared to the flower of D. stramonium which is longer, up to 10 cm long.

Brugmansia species may be confused with Datura species. Brugmansias long-lived (perennial) while daturas are annual. Both plants have a trumpet shaped flower; but those of brugmansias point downwards while datura's flowers most often point upward. Brugmansias emit a sweet fragrance while datura's fragrance can be described as spicy or lemony.

Economic and other uses

Datura ferox can be grown as an ornamental plant. However, these uses cannot compensate for this plant's overall negative impacts.

Environmental and other impacts

Datura ferox is a poisonous weed that competes aggressively with crops in the field and pasture. All parts of Datura plants contain dangerous levels of poison and may be fatal if ingested by humans and other animals, including livestock and pets. D. ferox has been listed as a noxious weed in South Africa (prohibited plants that must be controlled. They serve no economic purpose and possess characteristics that are harmful to humans, animals or the environment) and several Australian states. In some countries of the world, it is also prohibited to buy, sell or cultivate Datura plants.

Management

The precise management measures adopted for any plant invasion will depend upon factors such as the terrain, the cost and availability of labour, the severity of the infestation and the presence of other invasive species. Some components of an integrated management approach are introduced below.

The best form of invasive species management is prevention. If prevention is no longer possible, it is best to treat the weed infestations when they are small to prevent them from establishing (early detection and rapid response). Controlling the weed before it seeds will reduce future problems. Control is generally best applied to the least infested areas before dense infestations are tackled. Consistent follow-up work is required for sustainable management.

Datura ferox can be managed by digging it up or otherwise removing it. It can also be sprayed with glyphosate. When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt consult an expert.

The editors could find no information on any biological control agents for this species.

Legislation

This species has been declared a noxious weed under the Noxious Weeds Act CAP 325, in Kenya. Accordingly the Minister of Agriculture can compel land owners who have such declared noxious weeds growing on their land to eradicate or have it otherwise removed. The editors are not aware of similar legislation in Uganda and Tanzania.

Notes

The species was first described in 1756 by Linnaeus. Ferox means "strongly fortified," referring to the fearsome-looking spines on the seed pod.

References

Allen, S., Nehl, D. (2002). Weedpak - a guide for integrated management of weeds in cotton.  www.cotton.crc.org.au.

Government of Kenya (1983). The Suppression of Noxious Weeds Act: CAP 325 of the Laws of Kenya. 2nd Ed. Government Printer, Nairobi, 5 pp.

Global Compendium of Weeds. www.hear.org/gcw. Hawaiian Ecosystems at Risk Project. Accessed March 2011.

Henderson, L. (2001).  Alien weeds and invasive plants. A complete guide to declared weeds and invaders in South Africa.  Plant Protection Research Institute Handbook No. 12, 300pp. PPR, ARC South Africa.

Wikipedia contributors. "Datura ferox L. ." Wikipedia, The Free Encyclopedia. Accessed January 2011.

Editors

Agnes Lusweti, National Museums of Kenya; Emily Wabuyele, National Museums of Kenya, Paul Ssegawa, Makerere University; John Mauremootoo, BioNET-INTERNATIONAL Secretariat - UK.

Acknowledgments

This fact sheet is adapted from The Environmental Weeds of Australia by Sheldon Navie and Steve Adkins, Centre for Biological Information Technology, University of Queensland. We recognise the support from the National Museums of Kenya, Tropical Pesticides Research Institute (TPRI) - Tanzania and Makerere University, Uganda. This activity was undertaken as part of the BioNET-EAFRINET UVIMA Project (Taxonomy for Development in East Africa).

Contact

BioNET-EAFRINET Regional Coordinator: [email protected]