Rumohra - Dryopteridaceae

Rumohra adiantiformis (G. Forst.) Ching

 

 

 

 

Synonyms

Polypodium adiantiforme G. Forst.
Dryopteris adiantiformis (G.Forst.) Kunze

Common name

Knysna fern

Description

Rhizome widely creeping above ground, up to 10 mm in diameter; rhizome scales up to 16 × 5.5 mm, margin entire, reddish-brown, ovate to lanceolate, hairpointed, dense. Fronds spaced, very coriacous, erect, rigid, shiny above, paler below. Stipe up to 50 cm long, matt pale brown, grooved above, set with brown ovate scales towards the base, subglabrous with age. Lamina deltate to broadly ovate in outline, basal pinnae basiscopically developed,tripinnatifid to quadripinnate, apex pinnatifid-deltate, up to 50 × 35 cm. Pinnules pinnatifid to dentate, ovate in outline, base unequally cuneate, upper surface glabrous, lower surface sparsely set with a few scales along the veins. Rhachis stramineous to brown, grooved, costae and costules scaly in young fronds. Sori round, large, usually one per lobe; indusia c. 2.2 mm in diameter, round, thick, coriaceous, peltate, glabrous, shed at maturity.

Notes

The secondary rhachis and costae do not have raised edges on the upper surface, the fronds are very leathery, the rhizome creeps above ground and is densely set in papery, rusty coloured scales.

Derivation

adiantiformis: shaped like Adiantum; unclear reference since the fronds of the species of the genus Adiantum do not compare to Rumohra adiantiformis.

Habitat

Among boulders in rocky outcrops in montane grassland, shaded forest floors and forest margins, scrub forest on rocky slopes.

Distribution worldwide

Africa, Madagascar, Comoro and Mascarene islands, Australia, New Zealand, Polynesia, South and Central America.

Distribution in Africa

South Africa, Zimbabwe.

Growth form

Epiphytic, lithophytic, terrestrial.

Literature

  • Burrows, J.E. (1990) Southern African Ferns and Fern Allies. Frandsen, Sandton. Page 320. (Includes a picture).
  • Crouch, N.R., Klopper, R.R., Burrows, J.E. & Burrows, S.M. (2011) Ferns of Southern Africa, A comprehensive guide. Struik Nature. Pages 488 - 489. (Includes a picture).
  • Jacobsen, W.B.G. (1983) The Ferns and Fern Allies of Southern Africa. Butterworths, Durban and Pretoria. Pages 457 - 458. (Includes a picture).
  • 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 139 - 140.
  • Roux, J.P. (2001) Conspectus of Southern African Pteridophyta. Southern African Botanical Diversity Network Report, 13 Page 123. (Includes a picture).
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