Prota 2: Vegetables/Légumes
Biol. Jaarb. 27: 225 (1959; ‘coeruleum’).
2n = 28, 42, 56
Acrocephalus caeruleus Oliv. (1875), Acrocephalus lilacinus Oliv. (1875), Haumaniastrum lilacinum (Oliv.) J.K.Morton (1962), Haumaniastrum quarrei (Robyns & Lebrun) J.K.Morton (1962).
Origin and geographic distribution
Haumaniastrum caeruleum is widely distributed in West, Central and East Africa; in southern Africa it is found in Malawi, Zambia, Angola and Zimbabwe.
The leaves of Haumaniastrum caeruleum are eaten as a vegetable in Sudan. The powdered leaves are put in water to sponge a person with high fever. The leaves are used to treat headache in Senegal and Ghana. The plant ash is used as a vegetable salt in Kenya. Mixed with oil the leaves are used as perfume in Sudan.
Perennial herb up to 1 m tall; stem quadrangular, 1 to several arising from small woody rootstock or from fibrous root system. Leaves opposite or in whorls of 3–4, sessile or with short petiole up to 2 mm long; blade linear or narrowly elliptical, 2–10 cm × 0.2–1.5 cm, base attenuate or cuneate, apex acute, margin serrate. Inflorescence a globose to cylindrical head arranged in a lax or dense corymb; head 0.5–2(–4) cm long, subtended by white or bluish leaf-like caudate bracts up to 2.5 cm long. Flowers bisexual, zygomorphic, 5-merous; calyx 1.5–2 mm long, 2 -lipped, enlarged in fruit; corolla 4–6 mm long, white, pink, blue or purple, 2-lipped, tube 3–4.5 mm long, lower lip 4-lobed; stamens 4; ovary superior, 4-lobed, style gynobasic, bifid at apex. Fruit consisting of 4 nutlets 1–1.5 mm long.
Haumaniastrum comprises 35 species and is confined to tropical mainland Africa, with a single species also occurring in Madagascar. Haumaniastrum caeruleum is very variable, with variation notably in leaf shape, colour of floral bracts and hair density and length. The variation is possibly related to the different ploidy levels reported.
Haumaniastrum caeruleum is found in moist localities in grassland and open woodland, and as a weed in fields, at 200–2100 m altitude.
Genetic resources and breeding
As Haumaniastrum caeruleum is widespread and fairly common throughout its area of distribution there is no serious threat of genetic erosion.
Haumaniastrum caeruleum is likely to remain a minor vegetable and medicinal plant.
• Burkill, H.M., 1995. The useful plants of West Tropical Africa. 2nd Edition. Volume 3, Families J–L. Royal Botanic Gardens, Kew, United Kingdom. 857 pp.
• Morton, J.K., 1962. Cytotaxonomic studies on the West African Labiatae. Journal of the Linnean Society - Botany 58(372): 231–283.
• Paton, A., 1997. A revision of Haumaniastrum (Labiatae). Kew Bulletin 52(2): 293–378.
• Paton, A., 1997. Classification and species of Platostoma and its relationship with Haumaniastrum (Labiatae). Kew Bulletin 52(2): 257–292.
Correct citation of this article:
Bosch, C.H., 2004. Haumaniastrum caeruleum (Oliv.) P.A.Duvign. & Plancke In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.