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

Poaceae - Panicoideae - Andropogoneae - Andropogoninae - Arthraxon P.Beauv.

Description :

  • Perennial or annual, often trailing
  • Leaf blade linear-lanceolate to ovate-lanceolate, cordate and amplexicaul at base; ligule an unfringed to fringed membrane (rarely)
  • Inflorescence of slender racemes, subdigitate, internodes and pedicels filiform to linear; spikelets usually paired, secund, in long-short combinations: one sessile, the other pedicelled, pedicels free from rachis
  • Sessile spikelet laterally compressed, falling with glumes; glumes ± equal in size, dissimilar, awnless; lower glume rounded on back, with or without 2 lateral keels, spinously muricate; upper glume laterally compressed
  • Florets 2; lower floret sterile, reduced to a hyaline lemma, awnless; upper floret bisexual, lemma less firm than glumes, hyaline, awned from low down on back, awn glabrous, geniculate; callus truncate, inserted into hollow top of internode; palea reduced or 0
  • Lodicules 2, fleshy, glabrous
  • Stamens 2 or 3
  • Ovary glabrous
  • Caryopsis terete
  • Pedicelled spikelet variable in form, male, sterile or vestigial
  • x = 9 (polyploidy)

Nomenclature:

  • Arthraxon P.Beauv.
    • Palisot de Beauvois: 111 (1812)
    • Stapf: 162 (1917)
    • Van Welzen: 255 (1981)
    • Clayton & Renvoize: 741 (1982)
    • Clayton & Renvoize: 353 (1986)
    • Gibbs Russell et al.: 56 (1990)
    • Watson & Dallwitz: 138 (1994)

Distribution & Notes:

  • Global : Species ± 7, Old World tropics, but mainly in India
  • Southern Africa : Species 1: Arthraxon lanceolatus (Roxb.) Hochst. var. lanceolatus, Mpumalanga

References:

  • CLAYTON, W.D. & RENVOIZE, S.A. 1982. Flora of tropical East Africa . Gramineae (Part 3)
  • CLAYTON, W.D. & RENVOIZE S.A. 1986. Genera graminum. Grasses of the world. Kew Bulletin . Additional series 13
  • GIBBS RUSSELL, G.E., WATSON, L., KOEKEMOER, M., SMOOK, L., BARKER, N.P., ANDERSON, H.M. & DALLWITZ. M.J. 1990. Grasses of southern Africa. Memoirs of the Botanical Survey of South Africa No. 58
  • PALISOT DE BEAUVOIS, A.M.F.J. 1812. Essai d'une nouvelle agrostographie . Fain, Paris
  • STAPF, O. 1917-1920. Gramineae . Flora of tropical Africa 9
  • VAN WELZEN, P.C. 1981. A taxonomic revision of the genus Arthraxon Beauv. ( Gramineae ). Blumea 27
  • WATSON, L. & DALLWITZ, M.J. 1994. The grass genera of the world , revised edn. CAB International, Oxon