Launaea taraxacifolia (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Vegetable
Medicinal
Forage / feed
Food security

Launaea taraxacifolia (Willd.) Amin ex C.Jeffrey

Protologue: Kew Bull. 18: 474 (1966).

Family: Asteraceae (Compositae)

Chromosome number: 2n = 18

Synonyms

Sonchus taraxacifolius Willd. (1804), Lactuca taraxacifolia (Willd.) Schumach. ex Hornem. (1819).

Vernacular names

Yanrin, African lettuce, wild lettuce (En). Laitue africaine, langue de vache (Fr).

Origin and geographic distribution

Launaea taraxacifolia occurs from Senegal east to Ethiopia and Tanzania. The Ethiopian highlands have been suggested as the place of origin, from where it was introduced elsewhere and spread as a weed. Launaea taraxacifolia has been domesticated as a leafy vegetable in Nigeria, and is also cultivated locally in Senegal and Benin.

Uses

Yanrin leaves are eaten fresh as a salad or cooked in soups or sauces. Amongst the Yoruba people in Nigeria soup made of yanrin leaves, called ‘efo yanrin’ is popular. Wild yanrin has hard leaves that are very bitter, whereas leaves of cultivated types are more tender and less bitter. In northern Nigeria plants are fed to nursing cattle to increase milk production, and yanrin is given to livestock to induce multiple births. A leaf extract mixed with breast-milk of a nursing mother is administered medicinally to cure partial blindness resulting from snake spit. In Benin it is used as a febrifuge. In Ghana the leaves are rubbed on the limbs of backward children to induce them to walk. In Nigeria the plant is sometimes burnt for its ashes, which are used as vegetable salt.

Production and international trade

Yanrin is mostly collected from the wild and only cultivated to a limited extent for home use and for local markets. Bundles of fresh yanrin leaves soaked in water and cooked leaves packed in balls can be found at local Nigerian markets. There are no records on production and trade.

Properties

The composition of yanrin leaves per 100 g edible portion is: water 84.3 g, energy 184 kJ (44 kcal), protein 3.2 g, fat 0.8 g, carbohydrate 8.3 g, fibre 2.0 g, Ca 326 mg, P 58 mg (Leung, W.-T.W., Busson, F. & Jardin, C., 1968).

In tests with animals in Ghana, leaves of Launaea taraxacifolia showed a cholesterol-lowering effect.

Description

Perennial herb up to 150 cm tall, with creeping root system; stem erect, often woody at base. Leaves at base of plant in a rosette, alternate on stem, without stipules, sessile, spatulate to elliptical in outline, 4–20 cm × (0.5–)1–9 cm, simple to pinnatifid, lower leaves tapering at base, higher ones auriculate, toothed. Inflorescence a 12–22-flowered head arranged in a branched synflorescence; peduncle up to 1 cm long; involucre with imbricate outer bracts and a single row of 5 longer, linear-lanceolate inner bracts 8–12 mm long. Flowers all ligulate; corolla with tube c. 5 mm long and ligule 6–7 mm long, golden yellow; stamens 5, anthers united into a tube; ovary inferior, 1-celled, style 2-branched. Fruit a cylindrical to fusiform achene 3–5 mm long, slightly beaked, ribbed, crowned by white pappus hairs 5–8 mm long.

Other botanical information

Launaea comprises about 55 species and occurs in Africa and south-western Asia, but a single species (Launaea intybacea (Jacq.) Beauverd) has been introduced and naturalized in the Caribbean region and Central America. Particularly northern and eastern Africa is rich in species. Launaea is placed in tribe Lactuceae subtribe Sonchinae, together with e.g. Reichardia and Sonchus.

Growth and development

After the seeds have germinated, the young plants initially form a rosette of leaves. Thick roots develop later on in the season. In cultivation these are left in the ground during the dry season. From the onset of the rainy season, new rosettes are formed along the roots. The rosette leaves are most liked as a vegetable in the early stages of growth when they are not yet very bitter. A flowering shoot develops from the rosette, and the stem leaves are less appreciated because they are very bitter, especially as they get older. Seed can be collected about 3–4 months after sowing. The pappus attached to the fruits allows their dispersal by wind. The germination percentage is low, which is compensated for by the production of thousands of seeds per plant.

Ecology

Launaea taraxacifolia is frequently found in disturbed localities in open savanna vegetation. Only in Ethiopia is it recorded from undisturbed localities in grassland with scattered trees at 1300–1700 m altitude. It seems to prefer slightly humid conditions. Launaea taraxacifolia is often referred to as a dry season vegetable. It tolerates drought rather well and can also grow on poor soils with a low water table. It prefers altitudes of 600–1000 m rather than the lowland regions. The plants need a sunny place and do not tolerate shade.

Propagation and planting

Removing the pappus from the fruits is a cumbersome process and since the seed germination percentage is rather low, vegetative propagation using the roots is common. Roots are cut in pieces of about 10 cm length and these are planted horizontally and entirely covered with soil; 30–50 cuttings may be planted in a bed of 10 m².

Management

Yanrin does not need much management because of its low water requirement. Once the plant has developed and starts producing leaves, regular harvesting is recommended. Little is known about the plant’s response to manure and fertilizer applications. Organic manure encourages production of quality leaves under irrigation. A yanrin crop should be kept under control because it can easily become a persistent weed with its perennial root system.

Diseases and pests

Grey mould (Colletotrichum sp.) can kill fully-grown plants, with devastating effect especially when the crop is grown in the shade.

Harvesting

Young large leaves from the rosettes are picked. Consistent harvesting of leaves promotes the production of new leaves and delays the initiation of flowering stems. As soon as these develop, production drops and the leaf size and quality deteriorate.

Yield

From a well-managed bed of 10 m² one may expect 15–20 harvests during a 6–7 month period, with a total yield of 20 kg. The seed yield is 0.3–0.6 kg per bed (before cleaning).

Handling after harvest

After the leaves have been harvested, they are either used fresh or they are boiled and rolled into balls for sale at the market.

Genetic resources

A limited number of germplasm accessions (root cuttings) collected in 1999 were established in the CENRAD live genebank in Nigeria for evaluation and observation. As long as no improved cultivars are available, there is no danger of genetic erosion of farmers’ selections. Sampling and research of the putatively wild populations in Ethiopia may reveal the origin and genetic variability of this vegetable.

Breeding

There is an urgent need for breeding and selection. Other than some farmers making their own selections, no breeding work is currently being done on yanrin.

Prospects

Yanrin is one of the traditional leafy vegetables that is important especially in Nigeria. Selection of plants with tender leaves of low bitterness would increase its popularity. Agronomic research is needed to further its domestication. Research into its cultivation as a vegetable and into the medicinal properties of this plant is warranted.

Major references

• Adebisi, A.A. & Ladipo, D.O., 2000. Popularization of neglected indigenous leafy vegetables among the Yoruba Tribe of South-West Nigeria. CENRAD Development Series 06. CENRAD, Ibadan, Nigeria.

• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 960 pp.

• Kilian, N., 1997. Revision of Launaea Cass. (Compositae, Lactuceae, Sonchinae). Englera 17: 1–478.

• Leung, W.-T.W., Busson, F. & Jardin, C., 1968. Food composition table for use in Africa. FAO, Rome, Italy. 306 pp.

• Schippers, R.R., 2000. African indigenous vegetables. An overview of the cultivated species. Natural Resources Institute/ACP-EU Technical Centre for Agricultural and Rural Cooperation, Chatham, United Kingdom. 214 pp.

• van der Zon, A.P.M. & Grubben, G.J.H., 1976. Les légumes-feuilles spontanés et cultivés du Sud-Dahomey. Communication 65. Département des Recherches Agronomiques, Koninklijk Instituut voor de Tropen, Amsterdam, Netherlands. 111 pp.

• van Epenhuijsen, C.W., 1974. Growing native vegetables in Nigeria. FAO, Rome, Italy. 113 pp.

Other references

• Beentje, H.J., 2000. Compositae (part 1). In: Beentje, H.J. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. pp. 1–313.

Sources of illustration

• Berhaut, J., 1974. Flore illustrée du Sénégal. Dicotylédones. Volume 2. Balanophoracées à Composées. Gouvernement du Sénégal, Ministère du Développement Rural et de l’Hydraulique, Direction des Eaux et Forêts, Dakar, Senegal. 695 pp.

• Busson, F., 1965. Plantes alimentaires de l’ouest Africain: étude botanique, biologique et chimique. Leconte, Marseille, France. 568 pp.

Author(s)

• A.A. Adebisi

Centre for Environment, Renewable Natural Resources Management, Research and Development (CENRAD), P.M.B. 5052, Jericho Hills, Ibadan, Nigeria

Correct citation of this article

Adebisi, A.A., 2004. Launaea taraxacifolia (Willd.) Amin ex C.Jeffrey. [Internet] Record from PROTA4U. Grubben, G.J.H. & Denton, O.A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. <http://www.prota4u.org/search.asp>.

Accessed 17 December 2024.

• See the Prota4U database.