Adiantum - Adiantaceae

Adiantum raddianum C.Presl

Photo: P. Ballings
Zimbabwe

Photo: P. Ballings
Zimbabwe

Photo: P. Ballings
Zimbabwe

Photo: P. Ballings
Zimbabwe

 

 

 

 

Synonyms

Adiantum cuneatum Langsd. & Fisch.

Common name

Description

Rhizome short, creeping, branched; rhizome scales 1.5 mm long, brown, lanceolate, entire. Fronds closely spaced to tufted, thinly herbaceous, erect or arching. Stipe up to 25 cm long, thin, shiny, dark brown to black, glabrous. Lamina 3-4 pinnate, triangular to broadly ovate in outline, 10-25 × 8-15 cm, hairless. Rhachis and stalks dark brown to black, hairless. Pinnules persistent, 1.2 × 1 cm, obtriangular to trapeziform with straight sides, base wedge-shaped, outer margin irregularly incised into rounded lobes with toothed margins, veins ending in the sinuses of the marginal serrations; stalklets brown, 1-3 mm long, hairless. Sori on the outer margins of ultimate segments, indusial flaps broadly overlapping the sori, kidney shaped to circular, c. 1.5 mm in diameter.

Notes

A. raddianum is 3-4 pinnate. The small persistent pinnules, serrated outer margin with the veins ending in between the serrations and the reniform to almost circular sori distinguish A. raddianum from similar species such as A. poiretii orA. capillus-veneris .

Derivation

raddianum: named after Guiseppe Raddi (1770-1829), Italian botanist who collected in Brazil from where the type originates.

Habitat

Terrestrial, shaded moist earthbanks, roadcuttings and streambanks in forest.

Distribution worldwide

Native to South America, now widely naturalised.

Distribution in Africa

Kenya, Malawi, Mozambique, South Africa, Swaziland, Tanzania , Uganda, Zimbabwe.

Growth form

Terrestrial.

Literature

  • Burrows, J.E. (1990) Southern African Ferns and Fern Allies. Frandsen, Sandton. Page 126. (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 436 - 437. (Includes a picture).
  • Jacobsen, W.B.G. (1983) The Ferns and Fern Allies of Southern Africa. Butterworths, Durban and Pretoria. Pages 232 - 233. (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. Page 70.
  • Roux, J.P. (2001) Conspectus of Southern African Pteridophyta. Southern African Botanical Diversity Network Report, 13 Page 77.
  • Schelpe, E.A.C.L.E. (1970) Pteridophyta. Flora Zambesiaca, 0 Page 113.
  • Verdcourt, B. (2002) Adiantaceae. Flora of Tropical East Africa, Page 64. (Includes a picture).
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