Dryopteris - Dryopteridaceae

Dryopteris rodolfii J.P.Roux

 

 

 

 

Synonyms

Common name

Description

Rhizomes probably short decumbent. Fronds to 75.5 cm long. Stipes chestnut coloured at base, straw coloured higher up, firm, to 305 mm long, to 5 mm in diameter, with scales, scales rust coloured, chartaceous, broadly attached, cordate, to 19 x 5 mm, narrowly to broadly ovate-caudate, apex threadlike, margin minutely toothed, often with a few glands and irregularly threadlike outgrowths. Lamina firmly herbaceous, to 2-pinnate-pinnatifid, broadly ovate to deltate-acuminate in outline, to 46 x 38 cm, with up to 8 pinna pairs, the basal pair longest or slightly shorter than the pair higher up. Pinnae petiolate, the petiole to 10 mm long, to pinnate-pinnatifid, near opposite to alternate, the basal pair basiscopically developed, inaequilaterally triangular to narrowly ovate, linear-acuminate towards the apex, to 21.7 x 8 cm, with up to 3 pinnule pairs. Pinnules, the basal pairs short petiolate, becoming sessile and eventually adnate and basiscopically decurrent towards the pinna apex, lanceolate to oblong in outline, apex rounded, to 6 x 2 cm, pinnatifid, but mostly lobed, upper surface more or less hairless, lower surface sparsely to moderately set with scales and hairs. Ultimate segments oblong-obtuse to oblong-truncate, 6–10 x 3–5 mm wide, margin toothed. Venation evident, the apices slightly thickened, ending in the teeth near the margin. Rhachis straw coloured, upper surface grooved, sparsely to moderately scaled, scales similar to but smaller than stipe scales. Pinna-rachises straw coloured, upper surface shallowly grooved, narrowly winged for most of the length, the wing with a conspicuously thickened margin, lower surface sparsely to moderately scaled, the scales sessile to short-petiolate, to 4 x 1.2 mm, minutely toothed. Costa upper surface shallowly grooved. Sori essentially in 2-rows on the pinnules, but often in 2-rows on the basal lobes in larger and more divided laminae, circular, to 1.8 mm in diameter at maturity, spaced, but often touching at maturity in smaller laminae, inframedial on vein branches; indusia brown to rust coloured, firmly papery, persistent, broadly ovate to reniform in outline, 1.6–2.6 mm in diameter, basally entire to wavy, erose distally.

Notes

Derivation

rodolfii: in honour of the Italian botanist Rodolfo Emilio Giuseppe Pichi-Sermolli (1912–2005) for his contribution to pteridology.

Habitat

High elevation species confined to the Hagenia-bamboo zone on Mt. Kenya and the Philippia-Hagenia forests on the Bale Mountains.

Distribution worldwide

See African distribution.

Distribution in Africa

Ethiopia, Kenya.

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 123.
  • Roux, J.P. (2012) A revision of the fern genus Dryopteris (Dryopteridaceae) in sub-Saharan Africa. Phytotaxa, 70(1) Pages 94 - 96. (Includes a picture).
  • Roux, J.P.; Shaffer-Fehre, M. & Verdcourt, B. (2007) Dryopteridaceae. Flora of Tropical East Africa, Pages 45 - 46.
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