For the identification of insects and other fauna and flora of South Africa.

Sunday, May 19, 2013

Strap-leaved Bulbine (Bulbine narcissifolia)

Family Asphodelaceae
The grey-green, laxly twisted leaves and compact inflorescence of yellow flowers and white bracts covering the flower buds, make the strap-leafed bulbine, Bulbine narcissifolia, a very attractive plant. This plant is hardy and water-wise and will offer a brilliant yellow flower display without requiring a lot of attention.
 Description

Bulbine narcissifolia is a succulent, stemless, perennial herb with a rhizomatous base. Plants grow singly or in small clumps. The grey-green leaves are strap-shaped, laxly twisted, semi-succulent and up to 350 mm long with a yellowish exudate. Several dense, many-flowered, spike-like inflorescences are formed from a plant during spring and summer. Flowering occurs mainly during February to April and September to November.

The compact inflorescences are erect and up to 500 mm tall with prominent white, membranous bracts covering the flower buds. The bright yellow flowers are star-shaped with bearded stamens and mature from the bottom of the inflorescence. The stalks of the old flowers and fruit are straight, erect and almost completely adpressed against the central axis of the inflorescence.

 Conservation status

Bulbine narcissifolia is not threatened and can be very common in certain areas throughout its wide distribution range. It often forms stands, especially in overgrazed areas and is very conspicuous during the flowering season.

Distribution and habitat

Bulbine narcissifolia occurs from the far eastern regions of the Western Cape, through the Eastern Cape, KwaZulu-Natal, Lesotho, Free State, North-West, Gauteng, Limpopo, Botswana and further north to Ethiopia. It favours grassland and frequently forms small to large colonies, especially in overgrazed areas.

Owing to its wide distribution, this species is suitable for cultivation throughout the summer rainfall region. It is both frost and drought tolerant and can cope with a wide range of temperatures. In dry, hot years, plants tend to be smaller and have fewer inflorescences than in years of good rainfall.

Certain populations from the Eastern Cape tend to be deciduous, with the leaves dying back during winter and new growth re-emerging in early spring.

 Derivation of name and historical aspects

The specific epithet, narcissifolia, means with leaves like a Narcissus (daffodil). This refers to the grey-green, strap-shaped leaves of this species that are reminiscent of those of many daffodil species.

The genus Bulbine comprises ± 73 species occurring in Africa and Australia. Whereas only six species are found in Australia, a total of 67 occur in southern Africa, with only five of these also extending into tropical Africa. The genus is therefore essentially a southern African entity. The genus is characterized by succulent plants with lax or compound racemes (flowers borne on stalks along an unbranched axis, lower ones opening first) of mostly yellow (rarely white, orange or pink) flowers with bearded stamens.

The most common Bulbine found in the horticultural trade is both the yellow and orange colour forms of B. frutescens. Several other species are also worthy of cultivation, for instance B. abyssinica, B. latifolia, B. natalensis and of course, B. narcissifolia.

Ecology

Like most other species in this genus, Bulbine narcissifolia is insect pollinated and frequently visited by bees.

Uses and cultural aspects

Bulbine narcissifolia is used medicinally by the Basotho and Griqua for wound healing and as a mild purgative. As with many other Bulbine species, the roots can also be taken to counteract vomiting, diarrhoea and urinary infections. It is also commonly used to treat diabetes, rheumatism and blood problems.