Prota 2: Vegetables/Légumes
Herb. brit. 1: 47 (1769).
2n = 18
Sonchus oleraceus L. var. asper L. (1753).
Prickly sow thistle, rough sow thistle, spiny sowthistle (En). Laiteron épineux, laiteron rude, laiteron piquant, lastron piquant (Fr). Serralha áspera, serralha preta, serralha espinhosa (Po).
Origin and geographic distribution
Sonchus asper is widespread in Africa (including Madagascar), Asia and Europe. In southern Africa it is widespread but infrequent. It has been introduced in the Americas and is now widespread there too.
The leaves are eaten as a cooked vegetable, or occasionally raw in salads. Sonchus asper and Sonchus oleraceus L. are used in the same way and are often mixed as they are difficult to distinguish. In the Mediterranean region and South-East Asia use of Sonchus asper as a vegetable is widespread, in Africa its use as a vegetable is reported from Madagascar, but it is probably used elsewhere too. The latex has been used to treat warts.
The leaves of Sonchus asper taste quite bitter and contain per 100 g edible portion: water 86 g, energy 111 kJ (27 kcal), protein 3.3 g, carbohydrate 2.0 g, fibre 3.6 g, Ca 99 mg, Mg 29 mg, P 49 mg, Fe 3.0 mg, Zn 0.9 mg, carotene 8 mg, ascorbic acid 63 mg (Guil -Guerrero, J.L., Giménez-Giménez, A., Rodríguez-García, I. & Torija-Isasa, M.E., 1998).
Sesquiterpene lactones, especially of the eudesmanolide type, have been isolated from both roots and aerial parts; several of these are known to be effective against Plasmodium falciparum, fungi and inflammations.
Annual or sometimes biennial herb up to 2 m tall; stem ridged, simple or branched. Leaves alternate, simple; blade oblanceolate, 4–30 cm × 1–9 cm, pinnately lobed with wide triangular lobes to toothed, base amplexicaul with rounded auricles, but basal leaves attenuate at base, apex acute; distal leaves smaller and less lobed. Inflorescence a stalked head, many arranged together in a lax, leafy corymb; involucre 12–14 mm long. Flowers bisexual, ligulate, yellow; corolla tube 6 mm long, ligule 4–5 mm long; stamens 5, anthers united into a tube around the style; ovary inferior, 1-celled, style 2-branched. Fruit a strongly flattened, ribbed, smooth achene up to 3.5 mm long, with white pappus 6–9 mm long. Seedling with epigeal germination; hypocotyl 0.5–1.5 cm long; cotyledons leafy, oblong-elliptical.
Sonchus comprises about 60 species, out of which 17 have been recorded in tropical Africa.
Sonchus asper is a weed of cultivated fields, and is also found in grassland, along lakeshores and on mud, at 750–2550 m altitude.
Sonchus asper, like Sonchus oleraceus, may be a host of insect pests and viral diseases that may affect crops, notably crops belonging to the Solanaceae and Asteraceae families. Harmful viruses of tomato and lettuce have been found in Sonchus asper in temperate regions, as well as a thrips species. Although Sonchus asper is a weed, it is generally not considered noxious in agriculture and horticulture.
Genetic resources and breeding
As Sonchus asper is widespread no genetic erosion is envisaged, even though it is mostly not very abundant throughout its range.
Although possibly underutilized as a vegetable, promotion of Sonchus asper is not recommended because of its weedy nature.
• 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.
• Burkill, H.M., 1985. The useful plants of West Tropical Africa. 2nd Edition. Volume 1, Families A–D. Royal Botanic Gardens, Kew, United Kingdom. 960 pp.
• Decary, R., 1946. Plantes et animaux utiles de Madagascar. Annales du Musée Colonial de Marseille, 54e année, 6e série, 4e volume, 1er et dernier fascicule. 234 pp.
• Guil-Guerrero, J.L., Giménez-Giménez, A., Rodríguez-García, I. & Torija-Isasa, M.E., 1998. Nutritional composition of Sonchus species (S. asper L., S. oleraceus L. and S. tenerrimus L.). Journal of the Science of Food and Agriculture 76: 628–632.
• Groves, R.L., Walgenbach, J.F., Moyer, J.W. & Kennedy, G.G., 2001. Overwintering of Frankliniella fusca (Thysanoptera: Thripidae) on winter annual weeds infected with tomato spotted wilt virus and patterns of virus movement between susceptible weed hosts. Phytopathology 91: 891–899.
• Helal, A.M., Nakamura, N., El-Askary, H. & Hattori, M., 2000. Sesquiterpene lactone glucosides from Sonchus asper. Phytochemistry 53: 473–477.
• Hidajat, E.B., 1993. Sonchus L. In: Siemonsma, J.S. & Kasem Piluek (Editors). Plant Resources of South-East Asia No 8. Vegetables. Pudoc Scientific Publishers, Wageningen, Netherlands. pp. 260–262.
• Pope, G.V., 1992. Compositae. In: Pope, G.V. (Editor). Flora Zambesiaca. Volume 6, part 1. Flora Zambesiaca Managing Committee, London, United Kingdom. 264 pp.
• Wilken, D. & Hannah, L., 1998. Sonchus asper (L.) Hill (Asteraceae): prickly sow thistle, spiny milk thistle. Santa Barbara Botanic Garden Factsheets. Colorado Plateau Field Station, Flagstaff, Arizona, United States. [Internet] http://usgssrv1.usgs.nau.edu/swepic/factsheets/Sonchus_oleraceus.pdf. Accessed October 2003.
Correct citation of this article:
Bosch, C.H., 2004. Sonchus asper (L.) Hill In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.