e-Key v3 - Tridentea
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Interactive keys to the identification of seed plants of southern Africa using keys based on plant morphology.

Apocynaceae - Asclepiadoideae - Ceropegieae - Tridentea Haw.

Description :

  • Dwarf succulents, tufted, forming compact clumps, rarely slightly rhizomatous
  • Stems decumbent, obtusely 4(-6)-angled, softly fleshy, smooth, glabrous to the naked eye, tubercles submammose, each bearing a thick, glabrous, subulate, widely spreading, caducous leaf 1.5-10.0 mm long (leaving a whitish scar), subtended by a patch of stipular hairs on either side sometimes extending along margin
  • Inflorescence glabrous, 1 per stem, arising near base of stem with 1-5 flowers developing in gradual succession on a stout, gradually lengthening peduncle and pedicels (up to 80 mm long), spreading to ascending
  • Calyx 5-lobed, glabrous or with few marginal cilia
  • Corolla rotate to campanulate, usually lobed to ± half of radius or less, 20-100 mm in diameter, with shallow, funnel-shaped depression in centre, outside glabrous, inside glabrous and smooth to slightly rugose or papillate (papillae often with apical cilia), margins usually ciliate
  • Corona 2-seriate, arising from staminal column, glabrous; outer corona of 5 ascending to spreading, dorsiventrally flattened, simple to bifid or trifid lobes, fused only at base to bases of inner lobes; inner lobes incumbent on anthers, usually much exceeding them and rising up above centre of style head, dorsiventrally flattened at least towards base (often cylindrical above), often with laterally flattened, ± deltoid dorsal 'fin' in lower half
  • Staminal column arising near base of corolla tube on short stipe; style head not produced beyond anthers, truncate depressed at apex
  • Anthers 2-locular, incumbent on top of style head, subquadrate, horizontal, without apical or lateral appendages
  • Pollinia nearly horizontal, D-shaped, with short caudicles, corpuscle winged, ± as long as broad
  • Follicles terete-fusiform, slender, mottled with purple, glabrous, smooth
  • x = 11

Nomenclature:

  • Tridentea Haw.
    • Haworth: 34 (1812)
    • Leach: 4 (1978)
    • Bruyns: 192 (1995)

Distribution & Notes:

  • Southern Africa : Species 8, Namibia, Botswana, North-West, Free State, Northern, Western and Eastern Cape

References:

  • BRUYNS, P.V. 1995. A re-assessment of the genera Tridentea Haw. and Tromotriche Haw. South African Journal of Botany 61
  • HAWORTH, A.H. 1812. Synopsis plantarum succulentarum . Taylor & Co., London
  • LEACH, L.C. 1978. A review of Tridentea Haw. ( Asclepiadaceae ). Excelsa, Taxonomic Series 2