Cucumis africanus

L.f.

Family
: Cucurbitaceae (pumpkin family)
Common names : wild cucumber, wild gherkin (Eng.); wilde agurkie, doringkomkommertjie (Afr.); monyaku (Pedi); mthangazana (Xhosa); isende-lenja, uselwa-lwemamba (Zulu)

Fruits

The fruits of this species, looking like small, prickly and striped cucumbers, were pickled and preserved in Old Cape kitchens.

Description
Perennial herb. Rootstock thick and woody. Stems annual, up to more than 2 m long, finely ridged, roughly whitish hairy, usually prostrate, but will climb on bushes and other support; cut twigs exude clear sap. Leaves broadly ovate, deeply 5-palmately lobed, 15-115 mm long, dull green, roughly hairy on both sides with bulbous-based hairs; crushed leaves non-aromatic. Leaf stalks finely ridged and roughly hairy, up to 80 mm long. Tendrils simple. Flowers pale to dark yellow with green veins, either male or female, both appearing on the same plant (monoecious). Male flowers in groups of 5-10, petals up to 9 mm long. Female flowers solitary, petals up to ± 11 mm long. Ripe fruit 30-80 x up to 3o mm, prickly, prickles up to 10 mm long, fleshy to hard, base flat; unripe fruit longitudinally striped dark and light green, maturing to greenish yellow or white, striped purplish brown or yellow, prickles mainly on dark bands; occurring in two distinct forms, either small, ellipsoidal, bitter and poisonous when ripe, or large, cylindrical, non-bitter and edible when ripe; flesh green and translucent, many-seeded. Seeds elliptic, about 4.5 x 2.5 mm, and 1 mm thick, cream-coloured.

Cucumis africanus

Distribution
C. africanus is indigenous to Africa and occurs from the woodlands of Angola and Zimbabwe to Namibia, Botswana and South Africa. In South Africa it is found in Limpopo, North-West, Gauteng, Mpumalanga, KwaZulu-Natal, Northern, Western and Eastern Cape. It is rare in Mpumalanga, KwaZulu-Natal and the Eastern Cape.

C. africanus is common on deep and well-drained soils such as white, red or brown sand, grey or red loam and gravelly or stony soil. It is also found on brackish soils with underlying limestone formations as well as blackish clay soil. It will grow well on seasonally moist alluvial soil. The lithology and geology have been described as granite and mica schist, calcrete, shale and quartzite. It can be found on limestone outcrops, as well as dolomite and red granite formations. C. africanus is common on flat ground, but is also found on moderate to steep slopes where it grows on the northern, eastern and southern aspects among rocks, and also on Kalahari dunes. It is common in drainage areas such as dry river beds and flood plains, along water courses, around pans and near water holes, and also in disturbed areas such as along roadsides.

With its wide distribution, C. africanus grows in a large variety of vegetation types. Collectors have recorded the following: Karoo and Karroid types such as Namaqualand Broken Veld, Karroid Merxmuellera Mountain Veld, also with Schmidtia kalahariensis, Salsola and species of drought-deciduous scrub as well as Renosterveld, grassland and False Grassland. Also listed are savanna and various kinds of woodland e.g. Kalahari Thornveld with Colophospermum mopane, Combretum, Terminalia and many species of Acacia. It is quite rare in the swampy coastal grassland of KwaZulu-Natal.

Derivation of the name
The genus name Cucumis is the Latin name for the cucumber which was already cultivated in Ancient Egypt. Cucumis is a genus of 32 species, indigenous mainly to Africa, also Asia, Australia and some islands in the Pacific. It includes two major commercial vegetable crops: C. sativus (cucumbers from Asia) and C. melo (melons from Africa and Australasia), and two minor ones: the West Indian gherkin (C. anguria) and the kiwano (C. metuliferus). These last two species became cultivated crops outside their native Africa.

The species name africanus refers to the natural distribution area of this plant. C. hookeri Naudin is regarded as a synonym of C. africanus.

The Cucurbitaceae consists of about 120 genera and 735 species that are cosmopolitan in mostly tropical and subtropical countries. Many species are cultivated and of economic importance as food plants such as pumpkin, watermelon and also cucumber and melon as listed above. Members of this family are annual or perennial herbs or shrubs (only one species is a tree). The leaves are alternate and variable and tendrils are almost always present. The flowers are mostly unisexual and white or yellow; they occur on the same plant (monoecious) or on separate plants (dioecious). The fruit often is an indehiscent berry (soft-shelled) or gourd (hard-shelled) with one to many, often flattened seeds. There are about 18 genera and 75 species of this family in southern Africa. The family name refers to the pumpkins, Cucurbita species, all originally from the Americas.

Ecology
C. africanus flowers and fruits from about September to May, but mostly in March. Some 120 fruit per plant have been observed. In southern Africa it grows from 150 to 2 115 m altitude in areas of very low to moderately high rainfall, from under 100 800 mm annually; one record from the KwaZulu-Natal coast is exceptional. It can withstand high soil temperatures (one collector measured 47.5°C at about noon), but thrives in partial shade where the leaves will be larger and somewhat less hairy. On a very hot day, the leaves have been observed to stand at a 90° angle to the soil surface. At least the underground parts are frost hardy. Bees visit the flowers, presumably other insects too.

Uses and cultural aspects
In South African traditional medicine the fruit, leaf or root of C. africanus is used as an emetic, purgative or enema for various ailments. The boiled leaf is used as a poultice. The plant has also been used as an animal medicine. The poisonous form of the fruit contains the bitter principle cucumin ; incidents of human and cattle poisoning have been recorded (Watt & Breyer-Brandwijk 1962). According to Meeuse (1962), there are three types of fruit with increasing amounts of the bitter substance.

The fresh young leaves are eaten as a pot herb by many rural people. Arnold et al. (1985) found that the leaves are rich in calcium, iron, nicotinic acid and vitamin C. The fruits have an overall nutrient composition slightly better than that of the cucumber and is sought after as a water source by the Khoisan of the Kalahari and in other dry areas. R.Marloth, the famous South African botanist, noted on his specimen no. 10040 (now in the National Herbarium), that he bought agurkies in a shop in Cape Town in January 1921. He found the flavour slightly acid and the odour of the pulp like real cucumbers.

The non-bitter fruits of C. africanus have been pickled and preserved at the Cape since the late 17th century. Recipes for these delicacies are found in several publications e.g. Rood (1994). The same recipes can be used for the cultivated West Indian gherkin, C. anguria var. anguria. This plant was taken by slaves from West Africa to the West Indies where it was domesticated.

Growing Cucumis africanus

This species is not discussed in any of the standard horticultural books on indigenous South African plants. However, its natural habitat and ecology can be used as guidelines. C. africanus is an unlikely subject for the suburban garden; it should be treated as a climber rather than as a prostrate plant with long runners. If seed of the non-bitter form with large fruit could be obtained, it should make an interesting addition to your collection of indigenous plants with edible fruit. Avoid the form with small, bitter and poisonous fruit!

References and further reading

  • Acocks, J.P.H. 1988. Veld types of South Africa, edn 3. Memoirs of the Botanical Survey of South Africa No. 57.
  • Arnold, T.H., Wells, M.J. & Wehmeyer, A.S. 1985. Khoisan food plants: taxa with potential for future economic exploitation. In Wickens, G. Plants for arid lands : 69-86. Royal Botanic Gardens, Kew.
  • Hutchings, A., Scott, A.H., Lewis, G. & Cunningham, A.B. 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. Ecolab, Botany Dept., University of Cape Town.
  • Kirkbride, J.H. 1993. Biosystematic monograph of the genus Cucumis. Parkway Publishers, Boone, North Carolina.
  • Meeuse, A.D.J. 1962. The Cucurbitaceae of southern Africa. Bothalia 8: 72-74.
  • Rood, B. 1994. Kos uit die veldkombuis. Tafelberg, Cape Town.
  • Van Wyk, B-E. & Gericke, N. 2000. People's plants. A guide to useful plants of southern Africa. Briza Publications, Pretoria.
  • Watt, J.M. & Breyer-Brandwijk, M.G. 1962. Medicinal and poisonous plants of southern and eastern Africa, edn 2. Livingstone, Edinburgh & London.

 

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