Prota 2: Vegetables/Légumes
Mant. pl. 1: 73 (1767).
2n = 48
Single-flowered purslane, small-leaved purslane, ten o’clock plant, chickenweed (En). Pourpier (Fr). Beldroega (Po). Kinyorwe (Sw).
Origin and geographic distribution
Portulaca quadrifida is widely distributed in Africa and tropical Asia, and it has been introduced into the warmer areas of the Americas. In Africa it is found in all countries, usually as a weed, rarely cultivated (e.g. in DR Congo and Rwanda).
The leaves and young shoots of Portulaca quadrifida are collected from the wild and are eaten raw. They have a mild pleasant flavour and are frequently used in salads. They are also consumed as a cooked vegetable. In India boiled leaves are mixed with sorghum or pearl millet flour in preparing a kind of bread. Plants are a good feed for pigs, chicken and other birds. Large types are sometimes planted as an ornamental (e.g. in Rwanda) or as a soil binder to prevent erosion (e.g. in Kenya). Medicinally Portulaca quadrifida is used less widely but has similar medicinal applications as Portulaca oleracea L. The general uses are as a diuretic, to treat rheumatism and gynaecological diseases, as a sedative, analgesic and cardiotonic, to treat fever, disorders of the urinary tract, worm diseases, as a tonic and choleretic, to treat dysentery, and to apply externally to ulcers, eczema and dermatitis.
The nutritional composition of Portulaca quadrifida is probably comparable to Portulaca oleracea. Portulaca quadrifida may contain oxalates in toxic quantities, which may cause death in livestock. In some soils it also tends to accumulate nitrates and thus should be consumed in moderate quantities.
Prostrate, mat-forming annual or short-lived perennial herb with much-branched, spreading, articulated, fleshy stems up to 30 cm long or longer, rooting freely from the nodes, often flushed reddish; nodes with a dense whorl of whitish hairs. Leaves opposite, simple, sessile, narrowly elliptical to ovate, 0.5–1.5 cm × 1–4 mm, apex obtuse to subacute, smooth, veins distinct. Flowers solitary at the tips of short lateral branches, surrounded by 4 involucral leaves and copious hairs, bisexual; sepals 2, ovate, 3(–6) mm long; petals 4, obovate, 3.5–10 mm × 4 mm, usually yellow (rarely pinkish); stamens 7–16, arranged in 1 whorl; ovary halfinferior, style usually with 4 arms. Fruit an obovoid capsule 2–3.5 mm long, dehiscing near the base leaving only a very thin persistent rim, many-seeded. Seeds semi-orbicular in outline, c. 1 mm in diameter, dull grey.
Portulaca comprises about 150 species, of which about 30 occur in tropical Africa, but opinions on species delimitation differ considerably. Particularly the group of species with alternate leaves is taxonomically difficult. Portulaca quadrifida is rather unique with its mat-forming habit, but it is very variable, particularly in stamen number and flower size. In Africa only Portulaca pilosa L. has a similar habit, but it has alternate leaves, 5 petals and more numerous stamens.
Like Amaranthus, Portulaca is characterized by the C4cycle photosynthetic pathway, which means a high rate of photosynthesis at high light intensity and temperatures. Fresh seeds need light for germination, but this requirement disappears in older seeds. Generative development seems not to be influenced by photoperiod. The flowers are said to open promptly at 10 a.m., hence the English name ‘ten o’clock plant’. Seeds of Portulaca quadrifida are easily spread by wind, water, with crop seeds or through bird droppings, and as a weed it is difficult to control because it also easily propagates from small fragments.
Portulaca quadrifida is found in the wild on bare patches and among rocks, on sandy or stony soils, from sea-level up to 2000 m altitude. It is often involuntarily introduced by the agency of man and readily occupies newly disturbed areas, compost and rubbish heaps and fields. In some African languages it is called ‘Lord of the rubbish heap’. It is tolerant of a wide range of soils but prefers sand or sandy loams.
Genetic resources and breeding
The wide distribution and large variation of Portulaca quadrifida points to great genetic flexibility that rapidly permits adaptation to new environments.
Portulaca quadrifida will remain a minor vegetable, only of importance when other vegetables are scarce. Its nutritional composition and medicinal properties deserve further investigation. Cultivation can not be recommended because it also can behave as an aggressive weed.
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Correct citation of this article:
Jansen, P.C.M., 2004. Portulaca quadrifida L. In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.