Anthocleista grandiflora

Gilg

Family: Gentianaceae
Common names:
forest fever tree, big-leaf fever tree, big leaf, forest big-leaf, cabbage tree, tobacco tree (Eng.); grootblaarboom, koorsboom, wildetabakboom (Afr.); mueneene (Tshivenda); geludzu/galudzu (Xitsonga); umhobohobo, luvungu (siSwati); mophala (Northern Sotho)

 

Flowers

Anthocleista grandiflora is a striking tree with a tall straight trunk topped with a crown of huge leaves. It needs a warm, sunny garden with plenty of water and protection from frost and cold winds.

25 year old tree at Kirstenbosch

Description
Anthocleista grandiflora is a medium to tall evergreen tree, 5–35 m tall, with a slender, straight, smooth, light grey or brown trunk, branching high up the trunk. Trees have long bare branches arching upward with leaves densely clustered at the ends, forming a rounded, spreading crown. It has very large, stiff, leathery simple leaves 150–700 mm long and 70–250 mm wide on average, with some leaves up to 1.35 m long and 0.5 m wide. The largest leaves are found on young trees or on low-level branches. The leaves are paddle-shaped; oblong, broader in the upper half and narrowing towards the base. They are the largest simple leaves of any tree in southern Africa. The specimens in Kirstenbosch National Botanical Garden drop a steady supply of giant yellowed leaves throughout the year, and some become playthings for visiting children.

Leaves

Flowers are fragrant, creamy-white with a green tube, turning yellow then brown with age, in branched terminal clusters. The corolla tube is up to 35 mm long, with 8–13 narrow spreading petals. A crown-like ring of joined stamens at the mouth of the corolla tube surrounds the fleshy green rounded stigma. The fruit is a fleshy, smooth, oval to egg-shaped, green berry, soft and yellowish brown when mature, up to 30 mm long, containing many small dark brown seeds. In habitat, trees flower in spring–summer (from September to January) and fruit from late summer into winter (January to June). The Kirstenbosch trees continue flowering into autumn (March–April). The flowers are attractive and sweetly scented, but are not noticed because they are so high up. They can be appreciated at Kirstenbosch thanks to the 80 year old tree in the Dell (planted in 1934) that has low-hanging branches on its southeastern side that bring them almost within our reach. This tree produces fruits but does not seed itself in the Garden, whereas the trees in the Lowveld National Botanical Garden in Nelspruit do. The reason for this lack of seedlings has not been explored.

Conservation status
Red Listed as Least Concern, Anthocleista grandiflora is not threatened.

Distribution and habitat
Anthocleista grandiflora occurs in forest and along forest margins, in kloofs, beside densely wooded streams, in patches of relict forest on hillsides and in open swampy places, in tropical and subtropical areas in East Africa, from Uganda and Kenya southwards to Zimbabwe, Mozambique, Swaziland, and South Africa where it is found in Limpopo and Mpumalanga. It also occurs in the Comore Islands and Zanzibar. It is common in medium to low altitude forest in mountainous regions with high rainfall, from sea level to 2 300 m altitude.

Derivation of name and historical aspects
The name Anthocleista is derived from the Greek anthos, meaning flower, and cleistos, meaning closed or shut up. This could refer to how the stamens with their joined filaments form a ring around the mouth of the corolla tube, closing it off, or it could refer to the fact that only a few flowers of the inflorescence are open at any time, so most of the flowers are still closed buds. The specific epithet, grandiflora means large flowered, from the Latin grandis, meaning large, and floreo, to flower.

 This species is called fever tree on account of it being used to treat malaria. Its other common names namely big leaf is self-explanatory, cabbage tree refers to how the clusters of large leaves at branch ends resemble a cabbage head, and tobacco tree refers to the superficial resemblance of the leaves to those of tobacco plants ( Nicotiana tabacum ).

The genus Anthocleista is a small genus of about 15 species of trees found mostly in tropical Africa, Madagascar and the Mascarene Islands. Anthocleista grandiflora is the only species found in southern Africa.

Ecology
In its natural habitat elephants eat the leaves and branches, birds, monkeys and fruit bats eat the fruits and bushpig eat the fruits that fall. Many different insects are attracted by the flowers, and many insect-eating birds are, in turn, attracted by these insects.

Uses and cultural aspects
In South Africa the tree is valued for its medicinal properties. The leaves and bark are used to brew a tea to treat malaria, and bark is chewed to treat diarrhoea, and used to treat diabetes, high blood pressure and venereal disease. In the Congo the leaf and leaf ash is used to treat wounds of teats. In Tanzania leaves are used to treat malaria and roots to treat diarrhoea.

The bark is used to treat epilepsy in Zimbabwe, and to treat diarrhoea, fever and hepatitis in Madagascar. The leaves are used as a tonic, but are laxative in large doses. The smoke of burning bark is inhaled to dispel bad spirits, and pieces of root are braided into the hair as a lucky charm. In vitro tests have shown leaf extract to have significant anti-bacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis , but show no significant anti-malaria activity.

The wood is whitish yellow, light, soft and easy to saw and work. It finishes and polishes well, but is brittle, not durable and attacked by termites, and is thus useless for anything but light construction, short-lived items or for crates, boxes, or firewood.

Leaves and infloresence

Growing Anthocleista grandiflora

Anthocleista grandiflora needs a warm, well-watered position, deep fertile soil and protection from frost and cold winds. Its ideal position is in a forest situation beside a perennial stream. It can be grown in full sun, or in shade. Under ideal conditions young trees can grow fast, reaching nearly 5 m in their first four years. Use it as a foliage plant to give a lush tropical effect, as a striking feature plant or a shapely shade tree, but bear in mind that it will develop into a tall tree. It is not suited to an exposed, dry, windy position or to small gardens, nor is it recommended as a street tree. They do not have aggressive roots, but are quite messy, dropping large leaves, flowers and fruits, and can produce root suckers at the base. Feed generously and regularly for rapid growth and lush heads of leaves.

Cape Town, with its nutrient-poor soils, lack of water in summer and strong winds, does not offer ideal growing conditions for Anthocleista grandiflora, nevertheless it has done well at Kirstenbosch, which has a perennial water supply and is protected from Cape Town's notorious southeast winds. The oldest tree is an 80 year old with a magnificent spreading canopy, planted in 1934 in the Dell, beside the perennial Bath Stream. There is a 25 year old nearby, which is a handsome specimen, nearly as tall as the older tree but still quite slender. Three more trees were planted, also 25 years ago, in a well-watered but more exposed position at the bottom of the Main Lawn, but these specimens are smaller than the Dell tree with more tatty, sparse crowns and they have branched lower down their trunks, some nearly at ground level, and not all of the Main Lawn trees have flowered yet. There are a number of 14 year olds in the Arboretum, a few of which are growing beside the nearly completed raised walkway, which will soon give visitors a close-up view of this tree's magnificent leaves and lovely flowers.

Propagate Anthocleista grandiflora by seed, cuttings or root suckers. Fruits are ripe when they become soft and yellowish brown. Where they are not being carried off and eaten by wildlife, they can be picked up from the ground beneath the parent tree. Cut open and clean off the pulp to release the small seeds. They germinate readily, and are best sown in spring or summer. Take hardwood or semi-hardwood cuttings, treat with rooting hormone and place in coarse river sand under mist. Root suckers can be removed from trees that have produced them and the shoot potted or replanted to form a new tree.

Acknowledgements : Willem Froneman, Lowveld National Botanical Garden, for sharing his experience in growing and propagating Anthocleista grandiflora .

References and further reading

  • Boon, R. 2010. Pooley's Trees of Eastern South Africa, A Complete Guide . Flora & Fauna Publications Trust, Durban.
  • Coates Palgrave, K. 1983. Trees of Southern Africa , second revised edition . Struik, Cape Town.
  • Flora of southern Africa via POSA online
  • Flora of Zimbabwe online: http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=144460. Accessed 3 February 2014.
  • Foden, W. & Potter, L. 2005. Anthocleista grandiflora Gilg. National Assessment: Red List of South African Plants version 2013.1. Accessed on 2014/02/05
  • Grant, R. & Thomas, V. 2000. Sappi Tree Spotting Bushveld . Jacana, Johannesburg.
  • Leeuwenberg, A.J.M. 1983. Loganiaceae. Flora Zambesiaca 7:1 http://apps.kew.org/efloras/namedetail.do?flora=fz&taxon=5530&nameid=13846. Accessed 5 February 2014.
  • Leeuwenberg, A.J.M. 1993. Anthocleista grandiflora . Flowering Plants of Africa 52: 2. Plate 2080.
  • Leistner, O.A. (ed.). 2000. Seeds plants of southern Africa: families and genera. Strelitzia 10. National Botanical Institute, Pretoria.
  • Mickleburgh, S.P., Hutson, A.M. & Racey, P.A. 1992. Old World Fruit Bats, an Action Plan for their Conservation . http://data.iucn.org/dbtw-wpd/html/old%20world%20fruit%20bats/cover.html. Accessed 5 February 2014.
  • Palmer, E. & Pitman, N. 1972. Trees of Southern Africa . A.A. Balkema, Cape Town.
  • Schmelzer, G.H. 2012. Anthocleista grandiflora Gilg. [Internet] Record from PROTA4U. Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l'Afrique tropicale), Wageningen, Netherlands.http://www.prota4u.org/search.asp. Accessed 3 February 2014.
  • Smith, C.A. 1966. Common names of South African plants. Memoirs of the Botanical Survey of South Africa No. 35.
  • Verdoorn, I.C. 1963. Anthocleista . Flora of southern Africa . 26: 135–137.

 

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Kirstenbosch NBG

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This page forms part of the South African National Biodiversity Institute's plant information website www.plantzafrica.com.


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