Haworthia mirabilis var. consanguinea
Introduction
Haworthia mirabilis var. consanguinea is a dwarf cliff-hugger, with numerous rosettes of light green, ovate-lanceolate, succulent leaves and a solitary inflorescence bearing white flowers in spring; found on cliffs in the Riviersonderend Mountains in the Western Cape. Best grown in containers.
Fig. 1. A close-up of a cluster of Haworthia mirabilis var. consanguinea growing on a cliff in the Riviersonderend Mountains near McGregor, during the dry season.
Description
Description
Plants are dwarf-sized, rosulate, prolific from the base, forming small, rounded clusters up to 50 mm in diameter and consisting of up to 12 heads. Rosettes 30–50 mm in diameter. Roots grey, terete. Leaves up to 35, soft, triangular, ascending-spreading to patent (forming nearly a right angle with the stem), shiny and pellucid with translucent, linear markings; upper surface rounded, lower surface boat-shaped (cymbiform), surface smooth, green, becoming brownish-red during dry periods; margin entire; apex acute to acuminate, mucronate (ending in a sharp point). The inflorescence is a raceme up to 150 mm long, 10-flowered in the upper half, the bracts white, clasping, up to 3 mm long, ovate-acuminate; pedicels 2 mm long. Perianth tubular, curved, ascending-spreading, 15 mm long, white with purplish green mid-stripe. Flowering is mainly from spring to early summer (October to November). Seeds are dispersed by wind in summer and early autumn.
Fig. 2. A struggling group of Haworthia mirabilis var. consanguinea growing in the Riviersonderend Mountains near McGregor during the dry season. Note the seedling of Curio crassulifolius.
Conservation Status
Status
Confined to the Riviersonderend Mountains (Western Cape), it is a local endemic that is classified as Rare. It is not threatened because the plants are well protected by their sheer, cliff-face habitat that is difficult to reach and its distribution falls within a greater conservation region.
Fig. 3. (Left) Cliffs in the Riviersonderend Mountains near McGregor, Western Cape, habitat of Haworthia mirabilis var. consanguinea. (Right) A cluster of Haworthia mirabilis var. consanguinea filling a narrow crevice.
Distribution and habitat
Distribution description
Confined to the mountains near McGregor and Greyton in the Western Cape. It grows mainly on south-facing, quarzitic sandstone cliffs of the Peninsula Formation, Cape Supergroup, as well as on shale of the Bokkeveld Group, at 1 000–1 500 m altitude. Plants are firmly rooted in the crevices and the size and shape of the clusters is dependent on the cracks and crevices. Temperatures are high in summer, 28–34°C. Winters are cooler but frost is absent. Rainfall occurs throughout the year but mainly in winter, ranging from 600–800 mm per annum in the form of cyclonic winter rain or thunder showers.
The associated vegetation consists of North Sonderend Sandstone Fynbos of the Fynbos Biome (Mucina et al. 2005). Associated cliff-dwellers include Aloe mitriformis, Curio crassulifolius, Cotyledon orbiculata, Crassula dejecta, C. nudicaulis and C. perforata.
Derivation of name and historical aspects
History
The plant was named by Adrian Haworth (1767–1833), British, succulent student, as Aloe mirabilis in 1804. In 1812 he transferred it to the genus Haworthia, this genus created by the Frenchman Duval in 1809 and named after Adrian Haworth. The species name mirabilis is Latin and means ‘wonderful’. The variety consanguinea was named by Bruce Bayer, former curator of the Karoo National Botanical Garden. The name is Latin and means ‘kindred’ or ‘related to’ and pertains to its likeness to the small, mountain-form of Haworthia turgida.
Haworthia mirabilis var. consanguinea differs from the other varieties in its softer, less retuse (shallowly notched) leaves. The others are not cliff-dwelling and are well camouflaged, with a sunken growth habit that makes them difficult to detect. They often occur under the protection of thorny nurse shrubs. This variety differs from the mountain-form of H. turgida in its narrow, elongate buds and brownish-red coloration of the leaves, typical of H. mirabilis.
Fig. 4. A cluster of Haworthia mirabilis var. consanguinea growing in a crevice (Left) and wedged in a crack (Right), on cliffs near McGregor, Riviersonderend Mountains.
Ecology
Ecology
Haworthia mirabilis var. consanguinea suckers freely from the base, forming dense clusters within the crevices. Unlike some other cliff-hugging species of Haworthia, the rosettes fill the cracks but remain within the crack. The leaves are green, becoming brownish-red during dry periods, reducing the absorption of light. Windows on the upper leaf surface allow deep penetration of light. Continual sprouting from the base is an efficient vegetative backup dispersal strategy for this harsh cliff-face environment. Detached clusters or heads will also root if they fall into a crevice.
Plants are long-lived, with soft leaves, withering from the base. The very fleshy leaves are soft, becoming turgid after rain, but channelled during dry periods, an adaptation to the dry summers.
The Inflorescence is ascending to spreading, the corolla white, attracting a flying insect that pollinates the flowers. The capsules ripen in summer and autumn, in time for the coming winter rain. The small, lightweight, angular seeds are dispersed by wind and are ideal for for getting caught in crevices. Germination occurs within 14–21 days.
Fig. 5. Haworthia mirabilis var. consanguinea growing with Curio crassulifolius. Note the reddish colour of the leaf and the large translucent windows.
Uses
Use
No medicinal or cultural uses have been recorded.
Growing Haworthia mirabilis var. consanguinea
Grow
The Riviersonderend haworthia is easily grown in containers and miniature gardens, where conditions can be controlled, and does well in cultivation. Grow in a slightly acidic, sandy soil and add ample organic fertiliser in autumn. Keep in dappled shade. Water should be provided throughout the year, but sparingly in summer. This is a rapidly dividing plant, that forms dense clusters.
Plants are easily propagated by division in late summer.
Sow seed in autumn, in a shallow tray, in a sandy mixture (e.g. peat, sand and polystyrene) and keep moist. Germination is within 3 weeks and when the seedlings are large enough to handle, transfer them to individual containers. Place them in a shady position but with full light. The south side of a building is ideal.
Plants are relatively disease free but aphids, slugs and snails can sometimes be a problem.
References
- Bayer, M.B. & Van Jaarsveld, E.J. 2001. Haworthia. In U. Eggli. (ed.), Illustrated handbook of succulent plants: Monocotyledons. Springer, Berlin.
- Bayer, M.B. 1999. Haworthia revisited, a revision of the genus. Umdaus Press, Hatfield.
- Mucina, L. & Rutherford, M.C. (eds) 2006. The vegetation of South Africa, Lesotho and Swaziland. Strelitzia 19. South African National Biodiversity Institute, Pretoria.
- Raimondo, D., Von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. & Manyama, P.A. (eds) 2009. Red list of South African plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.
- Scott, C.L. 1968. A new species of Haworthia. Journal of South African Botany 34: 1.
- Uitewaal, A.J.A. 1948. Haworthia batesiana Uitewaal sp. nov. The National Cactus & Succulent Journal 3(4): 101.
Credits
Ernst van Jaarsveld
Kirstenbosch National Botanical Garden (Retired 2015)
Babylonstoren Farm
Extraordinary senior lecturer and researcher,
Department of Biodiversity and Conservation, University of the Western Cape
January 2022
Plant Attributes:
Plant Type: Succulent
SA Distribution: Western Cape
Soil type: Sandy
Flowering season: Spring, Early Summer
PH: Acid
Flower colour: Green, White
Aspect: Shade, Morning Sun (Semi Shade), Afternoon Sun (Semi Shade)
Gardening skill: Easy
Special Features:
Drought resistant
Good potplant
Horticultural zones
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