Prota 2: Vegetables/Légumes
Fl. bordel., ed. 2: 93 (1821).
2n = 16
Valerianella olitoria (L.) Pollich (1826).
Cornsalad, lamb’s lettuce, European cornsalad (En). Mâche, doucette (Fr). Alface de cordeiro, alface de coelho, alface da terra (Po).
Origin and geographic distribution
Valerianella locusta is a native of Europe, temperate western Asia and northern Africa. It is widely cultivated, and has become naturalized in parts of the United States. It is occasionally cultivated in DR Congo, East Africa and Madagascar.
The most common use of Valerianella locusta is of whole young plants in salads. Alternatively plants are cooked or blanched. The stems of young inflorescences are edible as well.
Leaves contain per 100 g: water 93.1 g, energy 92 kJ (22 kcal), protein 2.0 g, fat 0.4 g, carbohydrate 3.4 g, fibre 0.8 g, Ca 35 mg, Mg 13 mg, P 49 mg, Fe 1.7 mg, thiamin 0.07 mg, riboflavin 0.08 mg, niacin 0.4 mg and ascorbic acid 35 mg (Rubatzky & Yamaguchi, 1997).
Erect, dichotomously branched annual herb up to 40 cm tall. Leaves opposite, simple, up to 7.5 cm long; blade of lower leaves broadly spatulate to ovate, apex obtuse, margin entire to sinuate. Inflorescence a dense, head-like cyme. Flowers bisexual, small; calyx reduced to minute teeth; corolla with slightly unequal lobes, white or pale blue; stamens 3; ovary inferior, 3celled. Fruit an achene up to 2.5 mm long.
Valerianella comprises about 50 species. Valerianella microcarpa Lois. is considered the only native species of sub-Saharan Africa and occurs in alpine vegetation in Kenya. Valerianella eriocarpa Desv., Italian cornsalad, which is closely related to Valerianella locusta, has a largely similar distribution and is occasionally cultivated in Europe and the United States.
Valerianella locusta is a weed of arable land in its area of origin. It prefers a fairly rich, light soil although it tolerates a wide range of soils and humidity. It is frost-resistant and reasonably adapted to subtropical climates, and in the tropics it can be cultivated only at higher altitudes.
Propagation is done by direct seeding in fine soil at a depth of 1 cm in rows 15 cm apart. About 1 g of seed is needed per m2. For home consumption, sowing should be done successively to ensure a continuous supply. Whole plants are harvested when they have 8–12 leaves. Alternatively ratooning is practised by cutting at 5 cm above ground level. Shading, sufficient moisture and nitrogen fertilizer will help to delay flowering. Overgrown plants will go to seed and re-seeding will take place.
Genetic resources and breeding
Many cultivars of cornsalad have been released in Europe and the United States. They fall roughly in 2 groups of, on the one hand hardy, rosette-forming plants and on the other hand productive, long-leaved cultivars that are more sensitive.
In highland tropical Africa Valerianella locusta may continue to be grown for home consumption or for the local market. It is likely to remain a vegetable crop of limited importance.
• Rubatzky, V.E. & Yamaguchi, M., 1997. World vegetables: principles, production and nutritive values. 2nd Edition. Chapman & Hall, New York, United States. 843 pp.
• van den Bergh, M.H., 1993. Minor vegetables. In: Siemonsma, J.S. & Kasem Piluek (Editors). Plant Resources of South-East Asia No 8. Vegetables. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 280–310.
• Wiersema, J.H. & Léon, B., 1999. World economic plants. CRC Press, Boca Raton, Florida, United States. 749 pp.
• Huxley, A. (Editor), 1992. The new Royal Horticultural Society dictionary of gardening. Volume 4. MacMillan Press, London, United Kingdom. 888 pp.
• Walters, S.M., 1976. Valerianaceae. In: Tutin, T.G., Heywood, V.H., Burges, N.A., Moore, D.M., Valentine, D.H., Walters, S.M. & Webb, D.A. (Editors). Flora Europaea. Volume 4. Plantaginaceae to Compositae (and Rubiaceae). Cambridge University Press, Cambridge, United Kingdom. pp. 48–56.
Correct citation of this article:
Bosch, C.H., 2004. Valerianella locusta (L.) Laterr. In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.