Dryopteris - Dryopteridaceae

Dryopteris tricellularis J.P. Roux

 

 

 

 

Synonyms

Common name

Description

Rhizome short, decumbent, sparsely branched, to 15 mm in diameter; rhizome scales dark brown, broadly attached, ovate to lanceolate in outline, base cordate to truncate, margin entire, with outgrowths, and/or with glands, the apex threadlike, to 15 x 7 mm. Fronds suberect to arching, to 1.1 m long. Stipes chestnut coloured at the base, rust to strawcoloured higher up, upper surface shallowly grooved, lower surface often with a low central ridge (in dried specimens), to 570 mm long, to 9 mm in diameter, with scales similar to those on the rhizome. Lamina firmly herbaceous, ovate to narrowly triangular in outline, to 3-pinnate, to 55.5 x 44 cm, with up to 18 pinna pairs. Pinnae petiolated, the petiole to 12 mm long, the basal pair inaequilaterally ovate to oblong-acuminate, lanceolate to oblong-acuminate towards the lamina apex, to 2-pinnate, the basal pair slightly shorter or longer than the pair above, basiscopically developed in the lower half of the lamina, to 33 x 18 cm, basally closely to widely spaced, often imbricate higher up, with up to 11 pairs of pinnules. Pinnules petiolate, the petiole to 2 mm long, narrowly triangular to oblong in outline, apex rounded, pinnatifid to 1-pinnate, the acroscopic pinnule on the basal pinnae to 8 x 3.5 cm, the basiscopic pinnule on the basal pinnae to 9 x 2.8 cm, widely to closely spaced. Ultimate segments spaced, oblong-obtuse, basiscopically decurrent, to 1.2 x 0.4 cm, lobed; lobes serrate, upper surface hairless or sparsely set minute hairs, lower surface closely set with minute hairs along the costae, costules, and veins. Venation pinnately branched in the segments, the vein branches pinnately branched, forked or simple near the apex, evident on the lower surface, ending in the teeth near the margin. Rhachis straw coloured, upper surface shallowly grooved, often with a central ridge on the lower surface (in dried material), becoming narrowly winged towards the apex, initially moderately to densely set with scales and hairs. Pinnae rhachis and costae upper surface shallowly grooved, narrowly winged along the entire length in smaller specimens, pronounced on the lower surface, lower surface moderately to densely set with scales and hairs. Sori circular, medial to inframedial on the vein branches, discrete at maturity, to 1.2 mm in diameter; indusia brown, firmly herbaceous, cordate to reniform, wavy to irregularly lobed, to 1.0 mm in diameter.

Notes

Derivation

tricellularis: refers to the predominantly 3-celled cylindrical hairs occurring on the frond axes and veins.

Habitat

Bamboo, forest habitats along streambanks and at waterfalls.

Distribution worldwide

See African distribution.

Distribution in Africa

Ethiopia, Kenya, Tanzania , Uganda.

Growth form

Terrestrial.

Literature

  • 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 124.
  • Roux, J.P. (2012) A revision of the fern genus Dryopteris (Dryopteridaceae) in sub-Saharan Africa. Phytotaxa, 70(1) Pages 106 - 108. (Includes a picture).
  • Roux, J.P.; Shaffer-Fehre, M. & Verdcourt, B. (2007) Dryopteridaceae. Flora of Tropical East Africa, Pages 48 - 49.
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