Asplenium - Aspleniaceae

Asplenium inaequilaterale Willd.

Photo: P. Ballings

Photo: BT. Wursten

Photo: P. Ballings

Photo: P. Ballings

Photo: JE. Burrows






Asplenium laetum sensu Sim
Asplenium brachyotus Kunze
Asplenium erectum Bory ex Willd. var. brachyotus (Kunze) Sim
Asplenium suppositum Hieron.
Asplenium laetum Sw. var. brachyotus (Kunze) Bonap.

Common name


Rhizome erect, up to 8 mm diameter; rhizome scales 2-3 x 0.6 mm, dark brown, entire, lanceolate in outline, apex tapering to a point. Fronds not proliferous, tufted, erect, herbaceous. Stipe up to 19 cm, stipe and rhachis pale to dark matt brown, hairless at maturity. Lamina 12-32 x 4-13 cm, pinnate and narrowly triangular-ovate in outline, lower pinnae not markedly reduced; apical segment lobed, crenate, tapering to a point. Pinnae 8-20 pairs, narrowly oblong to roughly lanceolate in outline, sometimes falcate, shortly petiolate, 1.5-6.3 x 0.7-1.2 mm, glabrous, base asymmetric with a well developed acroscopic lobe, apex acute, margins irregularly crenate. Sori 3-16 pair, linear, situated on each pinnae at 45 degrees to the costa, 2-7 mm long; indusium entire, membranous, linear to oblong, 0.5-1 mm wide.  


Differs from similar species by not having basal pinnae reducing in size, base strongly asymmetrical but the midrib does not form the lower margin for a significant distance.


inaequilaterale: unequally sided, the pinnae bases of this species are asymmetric.


Deep shade in moist evergreen forest. Terrestrial or lithophyte.

Distribution worldwide

Africa, Comoro Is., Réunion.

Distribution in Africa

Angola, Burundi, Cameroon, Central African Republic, Dem. Republic of Congo, Equatorial Guinea (incl. Bioko), Ethiopia, Gabon, Ghana, Guinea, Kenya, Liberia, Malawi, Mozambique, Rwanda, Sierra Leone, South Africa, Sudan and South Sudan, Swaziland, Tanzania , Togo, Uganda, Zambia, Zimbabwe.

Growth form

Lithophytic, terrestrial.


  • Beentje, H.J. (2008) Aspleniaceae.Flora of Tropical East Africa, Pages 38 - 39. (Includes a picture).
  • Burrows, J.E. (1990) Southern African Ferns and Fern Allies. Frandsen, Sandton. Pages 222 - 223. (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 602 - 603. (Includes a picture).
  • Fisher, E. & Lobin, W. (2023) Synoptic Revision of Aspleniaceae (Asplenium, Hymenasplenium) of Rwanda. Magnolia Press, New Zealand. Page 19.
  • Jacobsen, W.B.G. (1983) The Ferns and Fern Allies of Southern Africa. Butterworths, Durban and Pretoria. Pages 347 - 348. (Includes a picture).
  • Kornas, J. (1979) Distribution and ecology of the Pteridophytes in Zambia. Polska Akademia Nauk Wydzial II Nauk Biologicznych. Page 100.
  • 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 88.
  • Roux, J.P. (2001) Conspectus of Southern African Pteridophyta.Southern African Botanical Diversity Network Report, 13 Page 166.
  • Schelpe, E.A.C.L.E. (1970) Pteridophyta.Flora Zambesiaca, 0 Page 176. (Includes a picture).