Gnetum buchholzianum

A fast-growing evergreen climbing vine reaching 10 m (32 ft) with a spread of 0.4 m (1 ft 4 in). Not self-fertile. Hardy to UK zone 10. Accommodates light sandy, medium loamy, and heavy clay soils with good drainage. Tolerates mildly acidic, neutral, and basic soil pH. Grows in full shade, semi-shade, or full sun and prefers moist soil.

Description

A climber. It is an evergreen plant. The stems can be 10-15 m long. The branches are thickened at the nodes. The leaves are opposite but each pair is at right angles to the next one. They can be in rings of three. The leaf blade is narrowly oval and 8-15 cm long by 4.8 cm wide. The base is rounded and they taper to the tip. The leaves are dark green above and paler underneath. They have 4-8 pairs of strongly curved veins. The flowers are in a spike in the axils of leaves or near the ends of branches. The flowers are of separate sexes. The seeds are narrowly oval and 10-15 mm long by 4-8 mm wide. They have a fleshy covering. They turn orange or red when ripe.

Edible Uses

The leaves can be eaten raw or cooked and are valued throughout the parts of Africa where the plant grows. They are most commonly eaten finely shredded in soups or made into condiments, though they can also be consumed raw. Because the leaves are rather tough, they are often mixed with waterleaf (Talinum triangulare) to soften them. Shredded leaves can be dried and preserved for later use. Leafy stems remain fresh for at least a week after harvesting. The leaves have a high nutritional value, providing protein, essential amino acids, and mineral elements. Their dry matter content is notably higher than that of other dark or medium green leaf vegetables, giving them a firm texture that leads some consumers to treat them as a meat substitute. The leaves of this species are somewhat thicker and darker green than those of the related Gnetum africanum. The fruit pulp and seeds are also edible; the mature seed is 15–15mm long and enclosed in a somewhat drupaceous, orange-tinted envelope. The tubers are sometimes eaten, particularly in times of scarcity. Climbing members of this genus in Asia yield a potable sap, and this species may be worth investigating in that regard as well.

Traditional Uses

The leaves are eaten raw or cooked. They are also added to sauces. The fruit and seeds are eaten. The leaves can be shredded and dried and stored for later use.

Medicinal Uses

The leaf is used to treat enlarged spleen, sore throat, piles, and high blood pressure, and acts as a cathartic. It is eaten to counter nausea and is considered antidotal against arrow-poison derived from Parquetina nigrescens. The leaves are chewed to reduce the effects of drunkenness and taken as an enema against constipation. Externally, chopped leaf is applied as a dressing on warts and boils to hasten maturation. The stem is cut into small pieces and infused to make a tisane taken to ease childbirth and reduce pain.

Known Hazards

Many Gnetum species are edible, with the seeds being roasted, and the foliage used as a leaf vegetable. The plant is harvested and yields a useful fiber. There is no sense of danger in consuming the fruit or the seeds. There is also a study done on the plant to see if it has any medicinal properties, finding some anti-coagulation effects due to its stilbenoid content. The family Gnetaceae is well known as a rich source of plant-derived stilbenoids as well as Cyperaceae, Dipterocarpaceae, Fabaceae, and Vitaceae.

Distribution

A tropical plant. It grows in rainforest from sea level to 1,200 m altitude. It suits humid locations. It does best with a rainfall of 3,000 mm per year. It needs shade. Plants do not grow well in full sun.

Where It Grows

Africa, Cameroon, Central Africa, Central African Republic, CAR, Congo DR, Congo R, Nigeria, West Africa,

Cultivation

A tropical plant. It grows in rainforest from sea level to 1,200 m altitude. It suits humid locations. It does best with a rainfall of 3,000 mm per year. It needs shade. Plants do not grow well in full sun. A plant of humid, lowland tropical rainforests, being found at elevations from sea level to 1,200 metres. It grows best in areas where the annual rainfall is around 3,000 mm. Succeeds in dappled shade in the woodland. Plants growing in full sun produce thinner leaves which are not so well liked by consumers. Cultivated plants need to be given some support, such as a tree, to grow into. The plant forms two distinct types of stem. Growing up from the base, the stems produce only small, scale-like leaves, and they grow rapidly towards the light. Higher up, side shoots are formed with fully-developed leaves. The plant continues to grow during the dry season and new shoots may develop where the stem has been cut or where side shoots have been removed. New shoots are also formed from rhizomes that spread along the forest floor. Current methods of harvest from wild stands are very destructive. Controlled harvesting, in which only side shoots or parts of stems are collected, allows new shoots to develop where a stem has been cut or where side shoots have been removed. Preliminary observations indicate that 3 - 4 harvests per year are possible, still allowing for substantial regrowth. More frequent harvesting will result in thin leaves that are considered inferior. The first harvest may take place 6 - 9 months after planting. The total lifespan of the plant is estimated at over 10 years. Preliminary observation indicates that in cultivation during the first harvest year the fresh leaf yield may reach 20 t/ha. This may double in subsequent years. Under wild conditions, the plant grows and forms underground tubers or roots that store plant food reserves. These can remain alive for many years when the vegetation and the plant growth above ground are cleared and the soil surface is laid bare. A dioecious species, both male and female forms need to be grown if fruit and seed are required.

Propagation

Seed is difficult to germinate under nursery conditions, though plants self-sow successfully in the wild. Propagation is also possible from cuttings.

Other Uses

The stem is supple and strong, used as rope, fashioned into traps and nooses for catching game, and made into straps for porterage.

Other Information

It is an important and commonly eaten vegetable. It is exported from Cameroon to Nigeria and other countries.

Notes

There are about 28 Gnetum species.

Nutrition

Synonyms

Also Known As

Afang, Anoh, Ecole, Eru, Fumbwa, Gelu, Ikoko, Ikokoh, Mokaka ko, Okazi, Okok, Ukasi

References (22)

• Bot. Jahrb. Syst. 40:519. 1908
• Burkill, H. M., 1985, The useful plants of west tropical Africa, Vol. 2. Kew.
• Busson, 1965,
• Food Composition Tables for use in Africa FAO http://www.fao.org/infoods/directory No. 673
• Grubben, G. J. H. and Denton, O. A. (eds), 2004, Plant Resources of Tropical Africa 2. Vegetables. PROTA, Wageningen, Netherlands. p 304

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