Combretum


Combretum, the bushwillows or combretums, make up the type genus of the family Combretaceae. The genus comprises about 272 species of trees and shrubs, most of which are native to tropical and southern Africa, about 5 to Madagascar, but there are others that are native to tropical Asia, New Guinea and the Bismarck Archipelago, Australia, and tropical America.
Around 17 species in the genus Quisqualis are very similar to Combretum and are now classified as species of the genus.
Though somewhat reminiscent of willows in their habitus, they are not particularly close relatives of these.

Ecology

Bushwillow trees often are important plants in their habitat. Savannahs in Africa, in particular those growing on granitic soils, are often dominated by Combretum and its close relative Terminalia. For example, C. apiculatum is a notable tree in the Angolan mopane woodlands ecoregion in the Kunene River basin in southern Africa.
Other species of this genus are a major component of Southwestern Amazonian moist forests. This genus contains several species that are pollinated by mammals other than bats, which is quite rare indeed. But most species are more conventionally pollinated by insects or birds.
Typhlodromus combretum, a mite of the family Phytoseiidae, was discovered on a bushwillow plant and is named after this genus. Other herbivores that eat Combretum foliage include the caterpillars of the Brown Awl which is found on C. albidum, C. latifolium and C. ovalifolium; those of the Orange-tailed Awl are recorded from C. extensum and C. latifolium.

Use by humans

Several species are used in African or Indian herbal medicine. Several species of this genus in Madagascar known collectively as voantamenaka or voatamenaka are used in traditional Malagasy medicine as deworming remedies. The class of chemical compounds known as combretastatins were first isolated from [Combretum afrum|South African bushwillow], from which they get their name. One synthetic derivative, fosbretabulin disodium, underwent preliminary study for the treatment of anaplastic thyroid cancer, but it was not effective enough to progress to more advanced trials. C. molle is also recorded to contain antioxidants such as punicalagin, which is also found in pomegranates, a somewhat related plant.
The botanist George Don studied this genus extensively. The Luvuvhu River in southern Africa was named after the river's bushwillows, locally known as muvuvhu.

Species

As of April 2021, there are 272 accepted species of Combretum: