Ledebouria mokobulanensis A.J.Hankey & T.J.Edwards
Common names: Mokobulan African hyacinth
An enigmatic, rare and range-restricted species from the high-altitude grasslands, on the crests of the Mpumalanga Drakensberg, in Mpumalanga Province, South Africa. This species was only recently named, after having being discovered by a local botanist who lives in the area.
Solitary, bulbous plant, with small bulbs, 18 × 23 mm, producing 1, or occasionally 2, deciduous, round leaves, which remain tightly appressed to the soil surface. The attractive leaves are mostly reddish green, with many, small pits, which are darker red, giving the leaves a very distinctive appearance. The intensity of the colour of the leaves is influenced by both drought and the amount of sun they receive. Pitted leaves are unusual in the genus and are only recorded from one other species of Ledebouria viz. L. galpinii.
A single, erect inflorescence (flower spike) is produced in early spring (August to September in South Africa), together with the emergence of the leaves. The unbranched inflorescence is topped by several, pale mauve to lilac, star-shaped florets (small flowers). The individual florets are each attached to the peduncle (main stalk) by a lilac pedicel (flower stalk). Purple to lilac filaments (anther stalks), extend from the mouth of the florets, which are topped off by pale yellow anthers, which release the pollen. The flowering period is limited to approximately 3 to 4 weeks, after which the seed is produced in small, purple-green capsules, which split open to release the small, dark brown, glossy, wrinkled seeds.
Ledebouria mokobulanensis is assessed as Vulnerable (VU) in the Red List of South African plants. The species is potentially threatened at all known localities by mining, expanding forestry plantations and over frequent fires.
Distribution and habitat
This species is a range-restricted endemic. It is known only from 3 locations, growing on and around the high peaks of the Mokobolwane Mountain Range, in the Lydenburg Centre of Plant Endemism (Lötter et al. 2002), along the Mpumalanga escarpment in Mpumalanga, South Africa. The species occurs in short, high-altitude grassland, between 2 000–2 200 m altitude, and steep rocky slopes, usually amongst rocks and grass. At such high altitudes, the grasslands are bathed in mist on a regular basis, especially during the wet summers. Much of the precipitation is received as condensation from this mist.
Derivation of name and historical aspects
The rare Mokobulan African hyacinth was discovered by Mrs Sandie Burrows, while collecting plant specimens in the botanically rich diversity, which abounds in the grassland habitats of the Mpumalanga highlands. The species was named by the author in 2008, after the Mokobulan Plantations where it was first collected. The species has subsequently been recorded on 2 other peaks of the same mountain range.
The genus Ledebouria is named in honour of the German-Estonian botanist, Professor Carl Friedrich von Ledebour (1785–1851). South Africa has 42 Ledebouria species. The genus is distributed across Africa, India and Madagascar, with the centre of species diversity in the eastern parts of southern Africa.
This species is most likely to be confused with Ledebouria galpinii, because of the size and shape of the plants, as well as the pitted leaf surface of the leaves. However, these 2 species are both range-restricted and are not recorded to occur outside of their narrow distribution ranges, which do not overlap. L. mokubulanensis is distinguished by the red, pitted surface of the leaves, which have a reddish green base colour, are broadly oval to round and appressed to the soil surface.
With the exception of Craib 2010, there is little published about the ecology of this little-known species. The brightly coloured flowers, which are open and star-shaped, suggests that they are opportunistically pollinated by most visiting insects. Honey bees and solitary bees have been seen visiting the flowers in cultivation. The seed is very small and roundish. Venter (1993) suggests that Ledebouria seeds are distributed by water wash.
This species is adapted to grassland vegetation, which experience burning on a frequent basis. The plants are able to survive fire by going completely dormant during the cold and dry winters, when fire is prevalent, while the bulbs remains protected under the soil. Craib 2010 suggested that the leaf markings and colouration of L. mokonulanensis may likely serve to camouflage plants from predators.
No specific references exist in the literature to this species being used by people. Plants in the genus Ledebouria as a whole has been used medicinally in Africa for purposes including pregnancy, diarrhoea, influenza, backache, skin irritations, wound treatment, as well as lumbago. The genus is also reported as being poisonous, although it is also reported that Bushmen eat the bulbs of certain other species (L. apertiflora and L. revoluta).
Growing Ledebouria mokobulanensis
Ledebouria mokobulanensis is easy to maintain in cultivation, although there is no record of it being grown out of its natural habitat, except at the Walter Sisulu National Botanical Garden, where it was grown for purposes of research into the species. Because of its small size, it is most suited to being grown in containers and prefers a well-drained, peaty, loam soil. An ideal potting mixture would include 1 part bark-based potting soil, 1 part peat (or peat alternative such as palm coir, bagasse or fern fibre), 1 part old, well-rotted compost or sifted cattle manure and 2 parts clay loam. The potting medium should provide a slightly acidic soil environment. Watering should be frequent during the summer months (preferably using rainwater if available). The plants prefer a cool, summer climate with good air circulation and the soil should be allowed to remain continuously damp in the growing season. Growing the plants in full sun will ensure an attractive and compact growth habit, as well as optimum leaf colouration. During the dry winter dormancy period, the pots should be watered only very lightly every 2 to 3 weeks to maintain some moisture content in the growth media. Watering can commence towards the end of winter at the onset of warmer temperatures (August–September in South Africa).
Propagation from seed is the best method of producing more plants; the seed must be sown fresh. Sow seeds immediately (do not store them) in spring or summer, in shallow seed trays filled with the sifted potting mixture mentioned above. Spread seed on a firmly tamped surface and lightly cover with the same mixture, approximately 2 mm deep. The trays should be kept in a bright, warm position out of direct sunlight and kept damp until germination has commenced. Seedlings can remain in the seedling tray or planted out as soon as they are large enough to handle. Flowering size bulbs can be attained after 2 to 3 years from germination.
- Craib, C. 2010. Ledebouria mokobulanensis, the jewel of the eastern Mpumalanga mist belt mountains. Penroc Newsletter December 2010 issue. http://www.penroc.co.za/newsletters2010/dec2010/dec10.html
- Hankey, A. 2011. Ledebouria Roth. PlantZAfrica. Internet 5 pp. http://pza.sanbi.org/ledebouria-genus
- Hankey, A.J. & Edwards, T.J. 2008. Ledebouria mokobulanensis A.J.Hankey and T.J.Edwards (Hyacinthaceae), a new species from the high altitude grasslands of Mpumalanga. South African Journal of Botany 74: 214–217.
- Hankey, A.J., Von Staden, L. & Lötter, M. 2007. Ledebouria mokobulanensis Hankey & T.J.Edwards. National Assessment: Red List of South African plants version 2015.1. Accessed on 2017/01/07.
- Venter, S. 2008. Synopsis of the genus Ledebouria Roth (Hyacinthaceae) in South Africa. Herbertia 62
Walter Sisulu National Botanical Garden
Plant Type: Bulb
SA Distribution: Mpumalanga
Soil type: Loam
Flowering season: Spring
Flower colour: Mauve/Lilac
Aspect: Full Sun
Gardening skill: Average