Asplenium - Aspleniaceae

Asplenium rutshuruense Taton ex Pic.Serm.

 

 

 

 

Synonyms

Common name

Description

Rhizome erect, 2-3 mm in diameter, loosely scaly; rhizome scales appressed, wide-triangular in outline, apex long tapering, base curved, margin uneven, 3-6 x 1.5-2 mm, heterotoechae (?), central area brown, cells with walls thickened with large lumen, marginal areas thin-membraneous, cells with smaller walls. Fronds monomorphic, loose, erect, 32–40 cm long, gemmiferous near the apex. Stipe rounded only on one side, deeply channeled above, 10-12 cm long, c. 1.5 mm diameter, smooth, base dense, loosely scaly above, basal scales similar to rhizome scales but smaller, scales towards apex gradually smaller, narrowly triangular. Lamina bipinnate, ovate-lanceolate in outline, 22-28 x 8-11 cm, olive on both sides; pinnae pluri-jugate, remote, triangular or oblong in outline, uneven, basiscopic side cut-to-arched, acroscopic straight, 4-5.5 x 1.2-1.8 cm, pinatifid; lobes remote, up to the top of the pinnae well spaced, the direction very variable, basiscopic lobes attached at a narrow angle, oblique, mostly converging, 1-4 lower forked, remaining undivided, narrowly oblanceolate-linear, base arched or curved, apex rounded, 4-9 x 1.2 mm, single vein spaced, one sora, acroscopic at an almost straight angle attached, generally straight, the base more broadly, pinnate or bifurcate, provided with 3-6 lobes, obtriangular or obovate, 2-4 sori, 1-3 proximal furcate, remaining undivided, narrowly oblanceolate-linear, rounded at apex, 6-11 x 1.2 mm, each vein spaced, one sora; rhachis almost cylindrical at base, nearly flat above, above deeply channeled; costa narrowly winged, equilateral from base to tip, below flat, very prominent above, sparsely scaled. Sori straight or arched, linear, 4 x 0.5 mm; indusium membranous minutely undulate-erose.
Translated from Latin, needs to be checked with specimens!

Notes

Differs from A. preussii by the larger size of the whole plant, by the lamina wider, ovate-lanceolate in outlin, by the pinnae longer and wider with the costa narrower and of the same width in all its lenght, by the segments longer and narrower, narrowly oblanceolate-linear, rounded at the tip, remote from each other, variously oriented, the acroscopic divaricate mainly straight, the basiscopic curved and falcate, by the sori linear, longer and narrower.

Derivation

rutshuruense: from the Rutshuru river in DRC, along which the plant was collected .

Habitat

In galerie forest along Rutshuru river, in shade.

Distribution worldwide

See African distribution.

Distribution in Africa

Dem. Republic of Congo.

Growth form

Terrestrial.

Literature

  • Pichi Sermolli, R.E.G. (1977) Fragmenta Pteridologiae VII. Webbia, 32 (1) Pages 81 - 83. (Includes a picture).
  • Roux, J.P. (2001) Conspectus of Southern African Pteridophyta. Southern African Botanical Diversity Network Report, 13 Page 96.
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