Click on images to enlarge
infestation (Photo: Sheldon Navie)
habit (Photo: Sheldon Navie)
seedling with simple leaves (Photo: Sheldon Navie)
habit in flower (Photo: Sheldon Navie)
immature fruit (Photo: Sheldon Navie)
mature fruit (Photo: Sheldon Navie)
close-up of mature fruit (Photo: Sheldon Navie)
flowers (Photo: Sheldon Navie)
younger stems and leaves (Photo: Sheldon Navie)
close-up of flower (Photo: Sheldon Navie)
older woody stems (Photo: Sheldon Navie)
close-up of older stem showing rootlets (Photo: Sheldon Navie)
leaves with clawed tendrils (Photo: Sheldon Navie)
close-up of seeds (Photo: Steve Hurst at USDA PLANTS Database)
Macfadyena unguis-cati (L.) A.H. Gentry
Bignonia acutistipula Schltdl.; Bignonia inflata Griseb.; Bignonia tweediana Lindl.; Bignonia unguis L. ex DC.; Bignonia unguis-cati L.; Doxantha unguis-cati (L.) Miers
Native to tropical America.
Macfadyena unguis-cati is invasive in parts of Kenya and Uganda (Global Invasive Species Database) and naturalised in parts of Tanzania (Dawson et al. 2008). M. unguis-cati is mostly found in riverine and wet coastal areas.
A weed of tropical, subtropical and warmer temperate regions. This species was introduced as a garden plant (ornamental) and is still often found growing in gardens. It is most commonly naturalised in riparian zones (banks of watercourses) and in disturbed rainforests, where it often smothers tall trees. Also found in open woodlands, plantations, waste areas, disturbed sites, along roadsides, and growing over fences and old buildings.
Younger stems are hairless (glabrous) and green in colour, often with reddish-brown or bronze coloured tips. The stems turn light brown or greyish and become woody as they age (old stems can be up to 15 cm or more thick). Older stems adhere to supports via short rootlets, while younger stems adhere to supports via the claw-like leaf tendrils.
The compound leaves are oppositely arranged and are borne on leaf stalks (petioles) 5-25 mm long. They consist of a pair of oval (elliptic) to slightly elongated (lanceolate) leaflets and a third 'leaflet' that has been modified into a small three-clawed tendril (each claw is 3-17 mm long). The leaflets (10-80 mm long and 4-30 mm wide) are hairless (glabrous) with entire margins and pointed tips (acute or acuminate apices). However, young seedlings have simple leaves with slightly toothed margins.
The showy bright yellow flowers (4-10 cm long and up to 10 cm wide) are tubular and have five petal lobes (corolla lobes), each about 1-2 cm long. These flowers usually have several fine reddish-orange lines in their throats. They also have five partially fused sepals (a calyx tube) 10-18 mm long. Flowers are borne singly or in small clusters originating in the leaf forks (in axillary clusters).
The fruit (15-50 cm long and 8-12 mm wide) are initially glossy green in appearance, but turn dark-brown as they mature. They are very elongated (linear), flattened, strap-like capsules (they are not pods). Each fruit contains numerous papery seeds (10-40 mm long and 4-10 mm wide). These oblong seeds have two see-through (translucent) wings that are not easily separated from the rest of the seed.
This plant reproduces by seed, as well as vegetatively via its tuberous root system that easily root at the nodes. Seeds are usually dispersed by wind and water, while the tuberous roots may be spread by floods and during human activities involving significant soil movement.
Macfadyena unguis-cati has been spread as an ornamental plant. This cannot compensate for this plant's overall negative impacts.
Macfadyena unguis-cati is a particularly aggressive invader in riparian zones (banks of watercourses) and rainforest plant communities. M. unguis-cati has the ability to completely smother native vegetation, garden trees, hedges, even growing up over tall trees, and many bushland areas. It can grow as a ground cover along the forest floor of scrub remnants and can form a thick carpet of stems and leaves which chokes out small existing plants and prevents the germination of all other species. The large climbing stems can also reach to the top of the rainforest canopy where, through a combination of weight and shading, they can cause the eventual death of the largest canopy trees. The vigorous and extensive root system, which produces large tubers at about 50 cm intervals, also adds to the invasiveness of this weed. M. unguis-cati has been included in the Global Invasive Species Database (GISD 2008). It 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 New South Wales and Queensland, Australia.
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.
Existing plants in the landscape should be removed, if possible before seeds are produced. Care must be exercised to prevent seed spread and dispersal during the removal process. Manual control is only practical on a very small infestation. Tubers on larger plants tend to break up when they are dug out. They can resprout. The disturbance of the control site can also disturb native vegetation.
Chemical control can be undertaken effectively for large infestations. Stems of individual vines can be cut close to the ground and the basal end should be painted with a suitable herbicide. The top section of the severed vines can be left on the tree if the vines are not too large. Otherwise they should be removed from the trunk and bundled together. Any regrowth can be foliar sprayed. Ground cover carpets of Macfadyena unguis-cati can also be foliar sprayed to great effect. Infestations treated in this way do not need to be cut and painted. When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt consult an expert.
A specialist leaf-tying pyralid moth (Hypocosmia pyrochroma) from Brazil and Argentina is currently being tested in quarantine for possible use as a biological control agent.
Not listed as a noxious weed by the state or governments in Kenya, Tanzania and Uganda.
Germplasm Resources Information Network (GRIN). www.ars-grin.gov/npgs/index.html. National Germplasm Resources Laboratory, National Genetic Resources Program, Agricultural Research Service (ARS), United States Department of Agriculture (USDA), Beltsville, Maryland, USA. Accessed March 2011.
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.
Lazarides, M., Cowley, K. and Hohnen, P. (1997). CSIRO Handbook of Australian Weeds. CSIRO Publishing, Collingwood, Victoria.
Agnes Lusweti, National Museums of Kenya; Emily Wabuyele, National Museums of Kenya, Paul Ssegawa, Makerere University; John Mauremootoo, BioNET-INTERNATIONAL Secretariat - UK.
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).
BioNET-EAFRINET Regional Coordinator: email@example.com