Rhoicissus tomentosa is a handsome, vigorous, evergreen tendril climber with ornamental, vine-like leaves and bunches of purple grape-like fruits.

Description
Usually a woody climber, or liane, with rope-like stems reaching the tops of 20 m high trees and looping from one to the other, occasionally forming a small tree 3-7 m in height. The bark is greyish and young branchlets are densely covered with thick, rusty hairs at first, becoming hairless with age. The tendrils are also velvety.

The leaves are simple and large, 90-200 x 70-160 mm, almost circular or wider than they are long, or kidney-shaped. The upper surface is deep green and hairless, whereas the under-surface is covered with soft, dense, rust-coloured hairs; occasionally these hairs are confined to the veins. The leaves are conspicuously 3-veined from the base.

The margin is sometimes entire but is usually shallowly toothed and slightly wavy, or conspicuously 3-lobed but not deeply divided. The petiole is velvety and up to 6 mm long. The young growth and new leaves are conspicuously covered in the velvety hairs and are richly coloured in shades of copper and purple. The old leaves turn crimson before falling.

The flowers are small, creamy green in colour and are clustered in dense heads on an approx. 20 mm long stalk. The buds are densely furry, covered with rust-coloured hairs. Flowering time is midsummer (Oct.-Jan.). The fruits look like grapes and grow in loose bunches; each one is an almost spherical, fleshy berry, up to 20 mm in diameter. They start out green but become red and then deep purplish black when fully ripe at the beginning of winter (May to June). The fruits are edible and pleasant-tasting but acidic with whitish flesh that is similar to that of the cultivated grape. Inside each fruit are 1-3 smooth, pear-shaped seeds, approx. 6 x 8 mm.

Distribution
This wild grape occurs from the Cape Peninsula, where it is abundant in the kloofs of the eastern slopes of Table Mountain, and along the coastline in a narrow strip all the way through the Eastern Cape up to northern KwaZulu-Natal and then inland through Mpumalanga into Limpopo Province, Zimbabwe and Malawi. It is almost always associated with forest and grows in riverine fringes where it clambers over trees and bushes.

Ecology
The fruits are eaten by birds and mammals and the leaves are browsed by game. The fruits are said to be particularly popular with Knysna and Purple-crested louries. The swollen tubers, although toxic, are eaten by bushpig and porcupines. Silver Striped Hawkmoth caterpillars (Hippotion celerio) have been recorded eating the leaves of Rhoicissus tomentosa and R. tridentata.

The leaves exhibit the phenomenon of guttation very well, when glistening drops of clear, watery fluid collect on the margins. This is best seen in early morning after humid windless nights. These drops of moisture are not dew (which is water that has condensed from the atmosphere onto the plant surfaces), but are drops of liquid forced out of the plant. When soil moisture is high and atmospheric conditions are not good for transpiration (evaporation of water via the leaves) root pressure builds up and the plant cannot rid itself of water fast enough so the liquid is pushed out of the tips of the veins in the leaves.

Derivation of the name
The name Rhoicissus is derived from the Greek rhoia, meaning pomegranate and kissos, ivy. Perhaps not the most accurate of names: like ivy, it is a climber, but it has tendrils; and the small fruits, although spherical, do not seem very like that of a pomegranate. The Latin species name tomentosa means felt-like, with a dense woolly covering, and alludes to the rust-coloured hairs that cover the young growth, the underside of the leaves, buds and tendrils. It has picked up an impressive number of common names, mostly regarding its resemblance to the cultivated grapevine, or its rope-like stems.

The grape family (Vitaceae) is a large, with approximately 1000 species spread throughout the warm countries of the world and is famous for its most celebrated member, the grapevine, Vitis vinifera. In southern Africa this family is represented by five genera (Ampelocisssus, Cayratia, Cissus, Cypostemma and Rhoicissus) and 53 species. In southern Africa, the genus Rhoicissus is represented by 10 species that occur in all the provinces of South Africa except the Northern Cape and all other southern African countries except Namibia and Botswana.

Rhoicissus tomentosa is relatively easy to tell apart from the others because it and only three of the other southern African species have simple or shallowly lobed leaves and it is the only canopy climber among them.

Other SA Rhoicissus species
The other three with simple leaves are:-

• R. laetans, the Blyde grape, whose leaves are elliptic with an entire margin, hairless, and blue-green, with prominent net-veining on the underside. It is usually a small shrub and it is endemic to the Blydepoort area in Mpumalanga.
  
  
• R. kougabergensis, the Kouga grape, has narrowly obovate leaves and reddish brown or transparent hairs. It is usually a spreading shrub and is endemic to the Kouga dam area in the Eastern Cape.
  
  
• R. microphylla has ovate to elliptic leaves, with the under-surface covered with reddish brown hairs. It is usually a small shrub and is found in the Queenstown-Cathcart area in the Eastern Cape.

All the other species are distinctly 3- to 5-foliolate and can be distinguished by the presence or absence of marginal teeth. Those with toothed margins are R. sekhukhuniensis (Sekhukhune grape), R. rhomboidea (glossy wild grape), R. tridentata (Bushman's grape) and R. sessifolia, and those whose margin is entire are R. revoilii (bushveld grape) and R. digitata (baboon grape).

Species with toothed margins:

• R. sekhukhuniensis: margin is coarsely and bluntly toothed, densely fringed with hairs, the terminal leaflet is obovate with the base tapering and the lateral leaflets are smaller with an asymmetric base. It is usually a shrub up to 3 m high, occasionally climbing. It is endemic to Sekhukhuneland in Mpumalanga and Limpopo.
  
  
• R. sessilifolia is usually a climber and is found in the coastal forests of KwaZulu-Natal.
  
  
• R. rhomboidea is a vigorous canopy climber, up to 20 m, occasionally a small tree 3-6 m tall, and is found in forest and forest margins and clearings in KwaZulu-Natal and the Eastern Cape, Swaziland, Mpumalanga, Limpopo, Mozambique and Zimbabwe.
  
  Its leaves are 3-foliolate; each tooth is tipped with an approx. 1 mm long point, and the leaflet apex tapers to a point. The leaves are leathery, glossy dark green above with pale russet hairs underneath. The side leaflets are asymmetrical with short stalks (1-4 mm).
  
  
  All young parts are covered with short, soft, russet hairs. The fruits are edible, small (up to 10 mm diam.) roundish and dark red to purple and ripen in late summer-winter (February to June).
  
  
• R. tridentata is usually a scrambling shrub 1-3 m tall, up to 10 m, and grows in coastal dunes, coastal forest, forest margins and grassy hillsides in the Western Cape, Eastern Cape, KwaZulu-Natal, Free State, Lesotho, Mpumalanga, Swaziland, Limpopo, North-West, Gauteng, Mozambique and into tropical Africa and Yemen. Its leaf size is very variable, is 3-foliolate and the side leaflets are usually symmetrical, with short stalks or none. Each tooth is tipped with an approx. 0.5 mm long point and the leaflet apex is square to rounded. The leaves are leathery, shiny dark green above and paler underneath with or without velvety hairs on the veins. The fruits are roundish, about 18 mm in diameter and ripen in late summer-winter (February to June).

The species with entire margins can be told apart by R. revoilii being 3-foliolate and the leaflet apex mostly tapering to a point, whereas R. digitata has some 5-foliolate leaves, although most are 3-foliolate and the leaflet apex is tapering to rounded and is usually notched. Further, each leaflet of R. revoilii has an approx. 20 mm long stalk whereas those of R. digitata do not, and the base of the lateral leaflets of R. revoilii are often markedly asymmetric and tendrils are seldom present but are frequently present on R. digitata.

Species with entire margins:

• R. digitata is a woody climber up to 15 m, occasionally a small, bushy tree 3 to 4 m tall, that is found in grassland, bush, on forest margins and on coastal dunes and dry sand forest in the Western Cape, Eastern Cape, KwaZulu-Natal, Mpumalanga, Swaziland and Mozambique.
  
  The leaflets have very short stalks, the middle leaflet is the longest, they are smooth dark green above and covered with fine russet hairs underneath, and the margin is entire. New leaves are conspicuously rust-coloured.
  
  Fruits are purplish black, small, roundish, approx. 15 mm diam. berries, that ripen in late autumn-winter (March to July).
  
  
• R. revoilii is a scrambling shrub or a small tree up to 7 m, occurring in mixed woodland and on rocky hills and koppies from sea level to 2 000 m in Limpopo, Gauteng, Mpumalanga, Swaziland and KwaZulu-Natal. It is very like R. digitata but differs in that it never has 5-foliolate leaves and each leaflet has a stalk up to 20 mm long. The fruit is a black, approx. 15 mm in diameter, fleshy berry, often with a warty or scabby surface, and ripens in winter-spring (June to Oct.).

At Kirstenbosch we have Rhoicissus tomentosa, R. rhomboidea and R. digitata growing in the garden.

Uses
Rhoicissus tomentosa is one of the best wild grapes, the fruits are edible and pleasant tasting but acidic. They are thought to have caused severe colic and diarrhoea in three children in Grahamstown, so should be eaten in moderation. The juicy, pulpy ripe fruits boiled with plenty of sugar (7 grapes to 30 g sugar) make a brilliantly coloured and delicious jam or jelly. A reasonable wine can also be made from the fruits, described as sour with a pleasant fragrance. The fruits are also used to make vinegar. The pliant branches are split and used as rope for tying down thatch and also in basket-making. Because of its close relationship to the vines of cultivation, it was tried out as stock for grafting in combating phylloxera in Cape vineyards in the 1800s but was not used, as its growth is much too slow. The tuberous rootstock is poisonous and is used in traditional medicine The roots boiled in milk are given to calves to expel intestinal worms. They may also be used during pregnancy to facilitate delivery, although R. tridentata is the more commonly used species for that remedy.

Growing Rhoicissus tomentosa

This vigorous, scrambling, evergreen climber is a good garden subject. It is easy to grow and has ornamental foliage, both in shape and colour, giving interest throughout the year. It can be used in place of ivy (Hedera helix) or Virginia creeper/Boston ivy (Parthenocissus quinquefolia) to cover a wall, but being a tendril climber it needs something, like a trellis, to hang on to. It can be grown over a fence to form a screen, or over a pergola or a trellis. It is an attractive groundcover in semi-shade or shade, or it can be allowed to form a large mounding shrub in the open. It is also a good hanging basket subject. It can be used to mimic topiary-take a topiary shape, fill it with soil using something to keep the soil inside, like you would a hanging basket, or use sphagnum moss but make sure it never dries out, punch holes in the netting and insert rooted Rhoicissus tomentosa cuttings. As it grows, weave the shoots through the netting or the wire pieces that make up the shape. Being accustomed to life on the forest edge or forest floor, it grows in low light and can be grown indoors.

Rhoicissus tomentosa can be propagated by seed, sown in spring-summer, or by stem cuttings taken in spring-summer, or by layering done in spring-summer.

References and further reading

• Coates Palgrave, M. 2002. Keith.Coates Palgrave Trees of southern Africa, edn 3. Struik, Cape Town.
• Fox, E.W. & Norwood Young, M.E. 1982. Food from the veld, edible wild plants of southern Africa. Delta Books, Johannesburg.
• Germishuizen, G. & Meyer, N.L. (eds). 2003. Plants of southern Africa: an annotated checklist. Strelitzia 14. National Botanical Institute, Pretoria.
• Hutchings, A. 1996. Zulu medicinal plants, an inventory. University of Natal Press, Pietermaritzburg.
• Jackson, W.P.U. 1990. Origins and meanings of names of South African plant genera. University of Cape Town Printing Dept., Cape Town.
• Palmer, E. & Pitman, N. 1972. Trees of southern Africa. Balkema, Cape Town.
• Pooley, E. 1993. The complete field guide to trees of Natal, Zululand and Transkei. Natal Flora Publications Trust, Durban.
• Retief, E. & Van Jaarsveld, E. 1997. A new species of Rhoicissus from the Eastern Cape. Bothalia 27: 49-51.
• Smith, C.A. 1966. Common names of South African plants. Memoirs of the Botanical Survey of South Africa No. 35. Department of Agricultural Technical Services, Pretoria.

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  Author Alice Notten, Kirstenbosch National Botanical Garden, June 2004