Haworthiopsis scabra var. starkiana
Haworthiopsis scabra (Haw.) G.D.Rowley var. starkiana (Poelln.) G.D.Rowley (= Haworthia scabra Haw. var. starkiana (Poelln.) M.B.Bayer)
Family: Asphodelaceae
Common names: Schoemanspoort haworthiopsis (Eng.), Schoemanspoort dwergaalwyntjie (Afr.)
Introduction
Haworthiopsis scabra var. starkiana is a dwarf cliff-hugger with numerous small rosettes of yellowish green, ovate-lanceolate, succulent leaves and a solitary inflorescence of white flowers in autumn; it grows on cliffs along Schoemanspoort in the Western Cape. Best grown in containers.
Fig. 1. A cluster of the Schoemanspoort haworthiopsis (Haworthiopsis scabra var. starkiana) growing on a cliff ledge at Schoemanspoort, north of Oudtshoorn in the Klein Karoo (Western Cape).
Description
Description
Plants rosulate, prolific from base, forming rounded clusters up to 500 mm in diameter and consisting of up to 10 heads. Rosettes up to 150 mm in diameter. Roots grey, terete. Leaves up to 30, firm, falcate (sickle-shaped), ovate to triangular-lanceolate, attenuate (gradually tapering to a point), ascending-spreading, laterally incurved (towards apex), up to 70 × 20 mm; surface yellowish green, smooth, shiny; apex mucronate (ending in a sharp, stiff point). Inflorescence racemose, up to 370 mm long, 18-flowered in distal half; bracts white, clasping, up to 3 mm long, ovate-acuminate; pedicels 2 mm long. Perianth tubular, 14–15 mm long, curved, ascending-spreading, white with purplish green midstripe. Flowering is mainly in early autumn (March to April). Seeds are dispersed by wind in summer and early autumn.
Fig. 2. A cluster of the Schoemanspoort haworthiopsis (Haworthiopsis scabra var. starkiana) growing on a broad cliff ledge at Schoemanspoort, in the Klein Karoo (Western Cape).
Conservation Status
Status
Haworthiopsis scabra var. starkiana is confined to the northeastern Klein Karoo region in the Western Cape. It is a local endemic, classified as Vulnerable (VU) in the Red List of South African Plants (Raimondo et al. 2009) but it can be regarded as not threatened because it is well protected by its sheer, cliff-face habitat and its distribution falls within a greater conservation region.
Distribution and habitat
Distribution description
Haworthiopsis scabra var. starkiana grows from Schoemanspoort in the northern Klein Karoo (adjacent to the Groot Swartberg) to near De Rust in the east (Western Cape). The habitat consists mainly of exposed, north-facing, sun-baked, sandstone cliffs of the Peninsula Formation, Cape Supergroup, at an altitude of 500–1 500 m. The cliffs have many ledges, crevices and fissures, ideal for establishment of plants. Plants are firmly rooted in crevices. Temperatures are high in summer (28–38°C). Winters are cooler but frost is absent. The average daily maximum temperature is about 25°C and the annual daily minimum about 8°C. Rainfall occurs throughout the year, ranging from 200–300 mm per annum in the form of cyclonic winter rain or thunder showers.
Fig. 3. A cluster of the Schoemanspoort haworthiopsis (Haworthiopsis scabra var. starkiana) growing on a ledge at Schoemanspoort, north of Oudtshoorn in the Klein Karoo (Western Cape).
The associated vegetation consist of Gamka Thicket of the Thicket Biome (Mucina et al. 2006) and associated cliff-dwellers include: Cotyledon orbiculata, Crassula perforata, Crassula rupestris, Ficus burtt-davyi and Portulacaria afra.
Derivation of name and historical aspects
History
Haworthiopsis scabra var. starkiana was named by Von Poellnitz in 1933 in Feddes Repertorium from plants sent to hm by Taylor. Gordon Rowley transferred it to his new genus Haworthiopsis in 2013. The species name scabra means ‘rough’, referring to the texture of the leaf. This variety is named in honour of Prof. Peter Stark (fl. 1934).
Although it has a limited distribution, Haworthiopsis scabra var. starkiana is very variable, showing genotypic plasticity and has many local forms. This is reflected in the work of Bayer (1999) who recognises 4 varieties of a variable H. scabra: var. scabra, var. morrisiae, var. lateganiae and var. starkiana. Haworthiopsis scabra var. scabra is not a cliff-dweller and the other varieties are regarded here as local variants of H. scabra var. starkiana. This genetic variability reflects its evolutionary ability to adapt to local conditions and colonise new habitats, should the opportunity arise. However, the extreme, exposed conditions have given them a narrow range of adaptations, resulting in these plants being not as easily cultivated as other species of Haworthiopsis and Haworthia.
Fig. 4. A small cluster of the Schoemanspoort haworthiopsis (Haworthiopsis scabra var. starkiana) growing on a cliff ledge at Schoemanspoort, during the dry period.
Ecology
Ecology
Plants divide to form large, conspicuous clusters on the exposed cliffs. The yellowish green leaves grow spirally twisted, shading out the copious amounts of sunlight it receives, especially during periods of drought and the dry season, protecting the inner portion of the rosette. Plants are long-lived, with hard, firm leaves that wither from the base. The fleshy leaves become turgid after rain, storing sufficient moisture to get them through dry periods, an adaptation to the extreme, dry habitat. The leaves have an entire leaf margin, ending in a hard, sharp point that would deter cliff-adapted animals, such as the rock dassie (Procavia capensis) and chacma baboon (Papio ursinus). Compared to Haworthiopsis scabra var. scabra, which is not a cliff-dweller, grows in fynbos and succulent karoo, and is well camouflaged with leaves covered in dense tubercles, there is some reduction in armament, the clusters are conspicuous (not camouflaged), the leaves glabrous, with entire margins, in response to living undisturbed in the inaccessible cliff habitat in contrast to accessible fynbos and succulent karoo vegetation.
The ascending to spreading inflorescence carries flowers with a white corolla, that attract a flying insect, resulting in cross pollination. The capsules ripen in winter, releasing the small, angular seeds during the cool period when there is ample rain, allowing the seeds to germinate when they land on a suitable crevice. Germination is in 14–21 days.
Haworthiopsis scabra var. starkiana suckers freely from the base, forming dense, rounded clusters. Continual sprouting from the base represents 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.
Uses
Use
No medicinal or cultural uses have been recorded.
Fig. 5. A close-up of a rosette of the Schoemanspoort haworthiopsis (Haworthiopsis scabra var. starkiana) in cultivation.
Growing Haworthiopsis scabra var. starkiana
Grow
Haworthiopsis scabra var. starkiana plants are not as easy to grow as other species of Haworthiopsis and Haworthia, because it has adapted to narrow extremes of its exposed habitat. In its native habitat, plants grow on cliffs, exposed to the harsh sun, in an area receiving only minimal rainfall. It is therefore very drought tolerant.
This variety can be propagated by seed or division. Plants can be divided by breaking up a cluster and transferring the rosettes to individual containers. Grow them in a sandy, slightly acidic soil medium and place in an area that receives lots of sunlight.
Haworthiopsis scabra var. starkiana is best grown in a container, in dry succulent karoo and thicket gardens. Outside its habitat, it should preferably be grown under controlled conditions, such as in a greenhouse. Plants should be placed in full sun and watered sparingly in winter and summer. The plants are slow growing and a liquid organic fertiliser can be added which will benefit its performance.
References
- Bayer, M.B. 1999. Haworthia revisited, a revision of the genus. Umdaus Press, Hatfield.
- Bayer, M.B. & Van Jaarsveld, E.J. 2001. Haworthia. In U. Eggli. (ed.), Illustrated handbook of succulent plants: Monocotyledons. Springer, Berlin.
- Eggli, U. & Newton, L.E. 2004. Etymological Dictionary of succulent plant names. Springer, Berlin.
- 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.
- Van Jaarsveld, E. 2000. Wonderful waterwise gardening: a regional guide to indigenous gardening in South Africa. Tafelberg Publishers, Cape Town.
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
February 2022
Plant Attributes:
Plant Type: Succulent
SA Distribution: Western Cape
Soil type: Sandy
Flowering season: Autumn
PH: Acid
Flower colour: White
Aspect: Full Sun
Gardening skill: Easy
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