Asplenium - Aspleniaceae

Asplenium hemitomum Hieron.

 

 

 

 

Synonyms

Asplenium christensenii Tardieu

Common name

Description

Rhizome shortly creeping or ascending, up to 3mm thick; rhizome scales narrowly ovate in outline, apex gradually tapering to a slender point and ending in an articulated hair, base cordate, dark brown, base and margin transparent, maximum c. 5 mm long and hardly more than 1/2 mm wide at the base. Fronds monomorphic, tufted, sub-coriaceous, 20-50 cm long. Stipe 10-23 cm long, more or less the same lenght as the lamina, dark grey, grooved in upper part, terete on the underside, set with scales similar to those of the rhizome at the base, more sparsely scaly with narrower and smaller scales towards the apex. Lamina imparipinnate, oblong in outline, 10-35 x 7-14 cm; pinnae 5-12 pairs, at an angle of 85° with the rhachis, (sub)opposite, petiolate, spaced, rhomboid and asymmetrical, 5-8 x 2-3 cm, base unequal, acroscopic base cuneate, subtruncate and ± auriculate, basiscopic base oblong and rounded, sometimes also auriculate, margin toothed, median lobe elongate (?), deltoid and toothed; terminal pinna often 3-lobed with acute lobes; pinnae with small narrow scales on lower surface; rhachis compressed, base often darkly blackish, towards the apex olive-green, sparsely set with fine scales. Sori linear in outline, 5-23 x 1 mm, set along the veins forming an angle of c. 30° with the costa, not reaching the margin or the costa, some opening towards the costa, some towards the margin; indusium membranous, entire, 0.5-1 mm wide.

Notes

Close to A. warneckei but A. hemitomum has longer rhizome scales, a more leathery texture and irregularly reticulate spores (crested in A. warneckei). Differs from A. cancellatum by having bigger, dark brown rhizome scales and a costa that is not prominent.

Derivation

Habitat

Shaded riverine forest.

Distribution worldwide

Africa, Principe, São Tomé.

Distribution in Africa

Angola, Cameroon, Central African Republic, Congo, Dem. Republic of Congo, Equatorial Guinea (incl. Bioko), Gabon, Ghana, Guinea, Ivory Coast, Liberia, Nigeria, Sierra Leone.

Growth form

Epiphytic.

Literature

  • Beentje, H.J. (2008) Aspleniaceae. Flora of Tropical East Africa, Page 68.
  • Hieronymus, G. (1912) Polypodiacearum species novae vel non satis cognitae africanae.. Botanische Jahrbücher, 46 (2) Pages 365 - 367.
  • Roux, J.P. (2009) Synopsis of the Lycopodiophyta and Pteridophyta of Africa, Madagascar and neighbouring islands. Strelitzia 23, South African National Biodiversity Institute, Pretoria. Pages 86 - 87.
  • Tardieu-Blot, M.-L. (1964) Ptéridophytes vol.3. Flore du Cameroun, Pages 203 - 204. (Includes a picture).
  • Thardieu-Blot, M.L. (1964) Ptéridophytes vol.8. Flore du Gabon, Page 135. (Includes a picture).
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