Asplenium - Aspleniaceae

Asplenium obscurum Blume

Photo: JE. Burrows
Zimbabwe

Photo: P. Ballings
Zimbabwe

Photo: P. Ballings
Zimbabwe

Photo: P. Ballings
Zimbabwe

 

 

 

 

Synonyms

Asplenium serriforme Mett.
Hymenasplenium obscurum (Blume) Tagawa

Common name

Description

Rhizome creeping, up to 5 mm thick; rhizome scales triangular in outline, margin subentire, apex pointed, up to 2 mm long. Fronds spaced up to 4 cm apart, erect, not proliferous. Stipe 12-35 cm long, with few scales similar to rhizome scales at base, stipe and rhachis glabrous, matt green or brown. Lamina 35 × 17 cm, pinnate, narrowly triangular to oblong in outline, basal pinnae not reduced. Pinnae in 15-20 pairs, 3.5-8.5 x 1.3-1.7 cm, membranous, petiolate, hairless, curved, margin toothed, rhombic in outline with costae forming the lower margins for about 1/3 of pinnae length, base unequal. Sori 11-30, linear to oval, 6-7 mm long, set at 45° to the costa about midway between costa and margin; indusium entire, membranous, narrowly oblong, 1 mm wide.

Notes

Confused with A. unilaterale; A. obscurum is larger, stipe matt-green not dark brown, costa forming the lower margin for a shorter distance.

Derivation

obscurum: dark, shady, indistinct; reference unclear.

Habitat

On moss covered rocks or terrestrial in deep shade along streams in evergreen forest.

Distribution worldwide

Africa, Madagascan region and Asia.

Distribution in Africa

Malawi, Mozambique, South Africa, Tanzania , Zimbabwe.

Growth form

Lithophytic, terrestrial.

Literature

  • Beentje, H.J. (2008) Aspleniaceae. Flora of Tropical East Africa, Page 29. (Includes a picture).
  • Burrows, J.E. (1990) Southern African Ferns and Fern Allies. Frandsen, Sandton. Pages 221 - 222. (Includes a picture).
  • Crouch, N.R., Klopper, R.R., Burrows, J.E. & Burrows, S.M. (2011) Ferns of Southern Africa, A comprehensive guide. Struik Nature. Pages 598 - 599. (Includes a picture).
  • Jacobsen, W.B.G. (1983) The Ferns and Fern Allies of Southern Africa. Butterworths, Durban and Pretoria. Pages 339 - 340. (Includes a picture).
  • Roux, J.P. (2001) Conspectus of Southern African Pteridophyta. Southern African Botanical Diversity Network Report, 13 Page 168.
  • Roux, J.P. (2009) Synopsis of the Lycopodiophyta and Pteridophyta of Africa, Madagascar and neighbouring islands. Strelitzia 23, South African National Biodiversity Institute, Pretoria. Page 92.
  • Schelpe, E.A.C.L.E. (1970) Pteridophyta. Flora Zambesiaca, 0 Page 174. (Includes a picture).
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