CEROPEGIA MACMASTERI, A NEW SPECIES OF CEROPEGIA FROM EASTERN CAPE, SOUTH AFRICA (ASCLEPIADOIDEAE - CEROPEGIEAE)
Ceropegia macmasteri A.P.Dold sp. nov., C. stentiae E.A.Bruce. affinis sed
But differs in having a stem reaching 60 mm, petiolate ovate to elliptic
spreading leaves 25 to 45 mm long and 20 to 30 mm broad, a pedicel reaching 2 to 4mm long, sepals up to 6 mm long, a green corolla tube with purple longitudinal lines and white-pubescence, globose-inflation at base up to 12 x 8 mm diam., purple bullate within, corolla lobes with a deltoid base and
linear-erect outer and inner corona lobes, purple at base, pale green above.
TYPE.--Eastern Cape, 3227 (Stutterheim): Middledrift farm, (-AC) 1 200 m, 24-11-2004, C. McMaster sub A. P. Dold 4699 (GRA, holo.).
Perennial non-succulent geophytic herb with tuber. Tuber depressed, spherical, ± 25 mm high, ± 50 mm diam. Stem single, up to 60 mm long, up to 3 mm thick at base, erect, glabrous, green, tinged pinkish at nodes, internodes 5-8 mm long. Leaves ovate at base of stem, 45-55 x 20-30 mm, younger leaves more elliptic, 25-45 x 10-15 mm, spreading, lamina glabrous, dark green, margin and lower midrib sparsely hispidulous; petiole 4.0-12.0 x 1.5-2.0 mm, shallowly grooved above, glabrous. Flowers single, extra-axillary at nodes, opening successively, with a single, green, linear-lanceolate bract, up to 4 x 1 mm at base; pedicels 2-4 mm long, up to 1.5 mm diam., recurved; sepals linear-lanceolate, up to 6.0 mm long x up to 1.4 mm at base, acute, green, tinged pinkish above, with sparse, small white bristles, spreading with incurved apices. Corolla 50-60 mm long; asymmetrically globose-inflated at base; inflation up to 12 x 9 mm diam., pale green with lines of purple
speckling and sparse pubescence externally, interior pale yellow-green, densely purple-bullate with a fringe of 1 mm long retrorse purple hairs at
constriction; tube abruptly up-curved above inflation, a narrow funnel up to 15 mm long, up to 5 mm diam. at base, broadening to 7 mm diam. at throat, pale green, striate with distinct purple lines, outer surface sparsely clothed with long spreading white hairs up to 1 mm long, deep reddish-purple within; lobes up to 35 mm long, 3.5 mm broad at base, base deltoid with purple lines
continuing from tube along margins and centre of lobes, narrowing over 2-4 mm to 0.4 mm broad, extended into attenuated lobes up to 30 mm long,
connivent-erect, connate at tips forming a cage, up to 1.6 mm broad near
apices, margins recurved with sparse long white hairs on outer surface and margin, green. Gynostegium cupular, up to 1.0 mm high, up to 1.6 mm diam. at base, pale green; outer corona lobes linear-erect, ± 1.6 x 0.4 mm at base, bifid almost to base, lobules purple in basal half, pale green in distal half; inner corona lobes linear-erect, ± 2.0 x 0.4 mm at base, adpressed to backs of
anthers, then connivent and erect forming a column in centre over style-head, slightly longer than outer lobes, apices divergent, purple at base, pale green above, glabrous. Pollinium ellipsoidal and flattened, up to 0.25 x up to 0.15 mm, with insertion crest along outer edge, golden brown; corpusculum oblong, up to 0.2 mm long, up to 0.1 mm broad, brown, broadly and transparently winged, caudicle short, narrow, brown. Flowering time: December to January. Figures 1-3
Diagnosis and relationships: Bruyns (1985) notes, notwithstanding Huber's (1957) revision and Dyer's (1980) Flora account, that the classification of the genus Ceropegia remains unclear and suggests that natural subdivisions within the genus would best be obtained by using aggregates of characters from all parts of the plant. Dyer's (1980) tentative classification is nevertheless followed here for the purposes of this description. The flowers of C. macmasteri most closely resemble those of C. zeyheri Schltr., and to a lesser degree C. fimbriata E.Mey. subsp. geniculata (Dyer) Bruyns, sharing the bulbous-inflated corolla base, the cage-like structure formed by the corolla lobes and the
linear-erect corona lobes. These species however, have fusiform fleshy roots rather than a tuber, a character used by Dyer (1980) and Bruyns (1985) to separate the genus into groups. Within the tuberous rooted group Dyer (1980) describes two further sub-groups based on whether or not the corolla lobes are free or fused at their apices, a character considered by Bruyns (1985) to be unreliable when examining herbarium specimens. Within the latter group C. macmasteri, neither a succulent nor a climber, is placed together with the erect, dwarf, herbaceous grassland species where the flower most closely
resembles C. stentiae E.A.Bruce in appearance. C. macmasteri is immediately distinguished from C. stentiae by having linear-erect corona lobes whereas that species has subquadrate, minutely three lobuled outer corona lobes and erect-spreading membranous inner corona lobes. Furthermore C. macmasteri has petiolate ovate to elliptic leaves and a green, pubescent corolla tube while C. stentiae has narrowly linear subsessile leaves and a glabrous, purplish-brown corolla tube.
Distribution and biology: This new species is only known from Middledrift farm near Cathcart (Figure 4) where it occurs together with Brachystelma cathcartensis, another rare localized endemic, in Moist Upland Grassland (Bredenkamp et al. 1996), also known as Dohne sourveld (Acocks 1988). Both species typically occur on the margins of exposed sandstone rock sheets (Beaufort series of the Karoo system) where there is less competition from the dense Themeda triandra and Tristachya hispida dominated grassveld. Farm
records show that the average annual rainfall on Middledrift farm is 750 mm, falling mostly in the summer months, and temperatures at this altitude, 1 200 m, vary between -5°C in winter and 34°C in summer (C. McMaster pers. comm..). Grass fires occur every four to six years. C. stentiae is only known from the Waterberg mountains in Northern Province.
A further search by the author and Nigel McMaster in 2005 indicates that the species is rare and solitary in habitat on Middledrift farm. Due to the small population size and small area occupied by the species an IUCN (2000)
category of Vulnerable (VUD2) is recommended. Cameron McMaster, after whom the species is named, is recognized as an important plant collector
having discovered several new plant and insect taxa in inaccessible and poorly collected areas in the Eastern Cape Province.
Rhodes University Joint Research Council is acknowledged for their support. Thanks to Dr Hugh Glen for providing the Latin diagnosis; Leigh-Anne De Wet for the line drawings and the McMaster family for their hospitality.
ACOCKS, J.P.H. 1988. Veld types of South Africa, 3rd edition. Memoirs of the Botanical Survey of South Africa No. 28: 94-96.
BRUYNS, P. V. 1985. Notes on Ceropegias of the Cape Province. Bradleya 3/1985: 1-47.
DYER, R.A. 1980. Asclepiadaceae. In O.A. Leistner (ed) Flora of South Africa 27,4: 31.
HUBER, H. 1957. Revision der Gattung Ceropegia. Mem. Soc. Bot 12: 1-203.
IUCN 2000. IUCN Red List Categories, prepared by the Species Survival Commission. IUCN, Gland, Switzerland.
BREDENKAMP, G., GRANGER, E., LUBKE, R. A. & VAN ROOYEN, N. 1996. Moist Upland Grassland. In A. B. Low & A. G. Rebelo, Vegetation of South Africa, Lesotho and Swaziland: 47-48. Department of Environmental Affairs and Tourism, Pretoria.
Selmar Schonland Herbarium, Rhodes University, P.O. Box 101, 6140 Grahamstown.