Prota 2: Vegetables/Légumes
Sp. pl. 1: 41 (1753).
Yellow commelina, wandering Jew, dayflower (En). Comméline, comméline africaine (Fr). Kongwa (Sw).
Origin and geographic distribution
Commelina africana is indigenous and widespread in Africa, occurring from Senegal to Ethiopia, and south to South Africa. It occurs also in Saudi Arabia, Yemen and Australia.
In Kenya, Uganda and Tanzania the leaves are cooked and eaten as a vegetable. They are chopped and boiled in water or in fresh or sour milk. Sesame seeds and groundnut paste are added for flavour and consistency. This vegetable is eaten with the staple food as a substitute for more preferred vegetables.
Many other uses are reported for Commelina africana. In Kenya and Tanzania the leaves are fed to livestock, especially pigs and rabbits. The flowers provide bee forage. In Kenya an infusion of the plant is used as a wash to reduce fever, and pounded stalks are used to treat colds and coughs in children. Fluid from the spathes is applied locally to cure eye diseases. The Zulu of South Africa bathe the body, especially of a child, with a cold infusion in cases of restless sleeping. Similarly, an infusion of the leaves is sprinkled over the resting place of a restless child in Zimbabwe. The Sotho in southern Africa take a decoction of the plant with Tephrosia capensis Pers. for treatment of a ‘weak heart’ and nervousness. In DR Congo the root is used for the same purpose. The plant cooked with Haplocarpha scaposa Harv., Helichrysum pilosellum (L.f.) Less. or the root of Cotyledon decussata Sims is given by Sotho as medicine to young women to cure infertility. Also, an infusion of the plant is drunk and its ash is rubbed over the loins as a fertility charm. In Zimbabwe and South Africa a concoction of the root is used as treatment for venereal diseases and to treat women with menstrual cramps. This preparation is also used for pelvic pains and bladder complaints.
Perennial herb with tuberous fusiform fleshy roots; stem creeping or straggling. Leaves arranged spirally, simple; leaf sheaths 0.8–3 cm long, with purple tinge, ciliate along the free margins; blade generally lanceolate, 6–11.5 cm × 1.2–2.2 cm, apex acute, glabrous except for the ciliate margins, rarely sparsely hairy, veins parallel. Inflorescence a leaf-opposed cyme; peduncle 8–40 mm long; spathe 0.9–2.4 cm long, margins free, glabrous except for the ciliate margins. Flowers bisexual, zygomorphic, yellow, rarely protruding from the spathe; lower petal linear-lanceolate, c. 5 mm × 2 mm, paired petals with claw 3–4 mm long, lamina broader than long, c. 4 mm × 6 mm; upper three stamens sterile, with cross-shaped anthers, medial stamen with filament 4–6 mm long and anther 1.5–2 mm long, the two lateral (lower) stamens with smaller anthers. Fruit a capsule 5–6 mm long, 3-celled, 3–5-seeded, the 2 ventral locules each 1(–2)-seeded (by abortion of the lower ovules) and dehiscent, the dorsal locule 1-seeded, indehiscent. Seeds variable in size, cylindrical-rectangular in outline, 2.2–3.5 mm × 1.3–2 mm, dark brown; testa rough (farinose granules) and pitted; hilum small, round.
Commelina africana is a variable species, in which many varieties are distinguished. The typical variety, var. africana, is a cultivated plant grown as a vegetable. Commelina africana is easily distinguished from the other Commelina species by its yellow instead of blue, purplish or pink flowers. The flowers open from 7–10 a.m.
Commelina africana occurs in secondary growth and disturbed localities, and as a weed on farms. In Senegal it grows in marshes. After the onset of the rains, the plant sprouts earlier than other plants and it is therefore useful as a fodder plant after prolonged drought. The same applies for its use as a vegetable; it is available earlier than commonly cultivated species.
In Uganda and Tanzania Commelina africana is not cultivated or protected by local people. It is common as a weed and therefore easily accessible. The leaves are collected in the rainy season for immediate use. They are not stored.
Genetic resources and breeding
No germplasm collections or breeding programmes are known to exist for Commelina africana. Because of its abundance in Africa, there is no danger of genetic erosion.
Despite its multiple uses, the plant is reported not to be marketed in Tanzania. It is not a very popular vegetable. Prospects for its development as a vegetable crop seem bleak.
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Correct citation of this article:
van der Burg, W.J., 2004. Commelina africana L. In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.