Prota 2: Vegetables/Légumes
2n = 80
Hibiscus calycinus Willd. (1800).
Lemon-eyed rose mallow (En).
Origin and geographic distribution
Hibiscus calyphyllus is widely distributed in Central, East and southern Africa, Madagascar and the Mascarene Islands, and occurs also in South Africa and Yemen. In Hawaii it is cultivated and naturalized in low-elevation dry areas. Elsewhere in the tropics and subtropics it is cultivated as an ornamental.
The leaves of Hibiscus calyphyllus are eaten as a vegetable, especially in East Africa. They are collected from the wild during the rainy season, wilted, chopped and boiled mixed with other coarse vegetables. This vegetable is eaten frequently locally, but in small amounts. In Uganda poles made from the stems are used for building by the Karamajong people. The bast fibre is made into rope in Uganda and Tanzania. Hibiscus calyphyllus is cultivated throughout the tropics and subtropics as an ornamental. In DR Congo the leaves are used in a mixture with several other plant species to prepare a cure for ganglions in domestic animals. In Kenya and Tanzania the leaves are applied to wounds as a dressing. The vapour of boiled roots is inhaled and the decoction drunk to treat pneumonia.
Perennial herb or shrub up to 3 m tall; stem with long hairs. Leaves alternate, simple; stipules threadlike, up to 1.5 cm long; petiole up to 9(–18) cm long; blade broadly ovate to orbicular, sometimes shallowly 3-lobed, up to 19 cm × 19 cm, base slightly cordate, apex acute, margin serrate, with stellate hairs. Flowers solitary in leaf axils, often congested at ends of branches, bisexual, regular, 5-merous; epicalyx segments 5, variable in shape, apex entire; calyx campanulate, up to 2 cm long; petals free, obovate, up to 6 cm long, pale yellow with red or purple base; stamens numerous, united into a column up to 1.2 cm long; ovary superior, 5-celled, style with 5 branches, included in the staminal column. Fruit an ovoid, beaked capsule up to 2.5 cm long, densely hairy, many-seeded. Seeds reniform, c. 4 mm × 3 mm long, shortly hairy.
Hibiscus comprises 200–300 species, mainly in the tropics and subtropics. Hibiscus calyphyllus belongs to section Calyphylli, which is characterized by its epicalyx of 5 segments. Hibiscus calyphyllus and Hibiscus ovalifolius (Forssk.) Vahl are sometimes considered conspecific, but might well prove to be distinct. The Hawaiian plants assigned to this species possibly deserve specific rank. Hibiscus calyphyllus does not occur at low altitudes and records of uses and properties of Hibiscus from the coast of East Africa probably do not refer to this species. Until a proper revision of section Calyphylli becomes available, identification of species remains difficult.
Hibiscus calyphyllus occurs in rainforest, riverine forest, thickets and grassland, along roadsides and on fallow land, up to 2100 m altitude. In Tanzania it grows in areas with an annual rainfall of 1100–1600 mm.
As a weed Hibiscus calyphyllus is not very important but it is an important host for the cotton pest spiny bollworm (Earias spp.). Wherever transgenic cotton with the Bt gene is grown, Hibiscus calyphyllus populations can be useful in conserving susceptible genes in the bollworm population to counteract resistance of the pest against the toxin produced by the transgenic cotton plants.
Genetic resources and breeding
There are few accessions of Hibiscus calyphyllus in genebanks. In its area of distribution the species is fairly common and not under threat of genetic erosion.
Hibiscus calyphyllus will remain a minor vegetable with only local importance. A taxonomic revision of Hibiscus is badly needed to avoid confusion in identifying species. Only Hibiscus section Furcaria has been revised recently, and even the delimitation of the genus and its sections is still unclear.
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Correct citation of this article:
Bosch, C.H., 2004. Hibiscus calyphyllus Cav. In: Grubben, G.J.H. & Denton, O.A. (Editors). PROTA 2: Vegetables/Légumes. [CD-Rom]. PROTA, Wageningen, Netherlands.