Dryopteris - Dryopteridaceae

Dryopteris occidentalis J.P.Roux

 

 

 

 

Synonyms

Common name

Description

Rhizome short-decumbent, to 75 mm long, to 6 mm in diameter, closely set with roots, persistent stipe bases and scales; rhizome scales dull rust coloured, thinly textured, sessile, broadly attached, narrowly triangular, narrowly ovate to filiform, to 9 x 2.4 mm, base narrowly to broadly wedge shaped, margin irregularly toothed, with scattered glands and with filiform outgrowths from the base. Fronds crowded, arching, to 95 cm long. Stipe straw coloured, to 38 cm long, to 4 mm in diameter, with scales, similar to those on the rhizome. Lamina narrowly ovate in outline, to 57 x 32.5 cm, 2-pinnate-pinnatifid, with up to 12 pinna pairs, distally the pinnae become sessile and eventually adnate and increasingly basiscopically decurrent. Pinnae stalked, the stalk to 10 mm long, proximally spaced to slightly overlapping, near opposite to alternate, the basal pinna pair longest, to 1-pinnate-pinnatifid, the basal pinna to 16.8 x 8 cm wide, the basal pinna pair basiscopically developed, inaequilaterally narrowly triangular to lanceolate, oblong acuminate to linear acuminate towards the lamina apex, with up to 4 pinna pairs. Pinnules stalked, the stalk to 3 mm long, proximally near opposite to alternate, widely spaced, pinnatifid, distally more closely spaced, progressively more shallowly lobed, ovate to oblong-acuminate. Ultimate segments sessile, broadly ovate, to 14 x 8 mm, lobed; lobes oblong-obtuse to oblong-truncate, to 8 x 4 mm, toothed, with minute glands and hairs along the veins. Venation immersed on the upper surface, evident on the lower surface, ending in the teeth near the margin. Rhachis, pinna rhachis and costae straw coloured, upper surface shallowly grooved, narrowly winged near the apex, sparsely scaled. Sori essentially in 2 rows on the pinnules, discrete at maturity, inframedial on the vein branches; indusia rust coloured, firmly herbaceous, reniform, to 1.6 mm in diameter, entire to strongly wavy, eglandular.

Notes

Derivation

occidentalis: western, reference to the distribution of the species in Africa.

Habitat

Montane forests.

Distribution worldwide

See African distribution.

Distribution in Africa

Guinea, Ivory Coast, Nigeria.

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 81 - 83. (Includes a picture).
  •