Seaweeds of the South African South Coast

 

 

 

 

 

 

 

 

 

 

 

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Order Gelidiales

Family Gelidiaceae

Gelidium pteridifolium R.E. Norris, Hommersand and Fredericq 1987: 375, figs 1-7, 10

Plants erect, fern-like, up to 20 cm tall, reddish-purple, stiff and cartilaginous; holdfast fibrous and bearing many upright, axes terete only at origin with holdfast, then subterete to compressed, becoming flattened distally and 1-3 mm wide; branching pinnate, branches constricted near base, bearing evenly-spaced (1-2 mm) short determinate branchlets of approximately equal size and appositely arranged, subtended at almost right angles to the axis with apices blunt to acute. Anatomy of darkly pigmented , small (to 6 µm diameter) outer cortical cells grading into large (to 10 µm) inner cortical cells that become angular; medulla of thick-walled angular cells up to 25 µm in diameter, united into filaments; bundles of refractive rhizines concentrated in inner cortex, almost absent from medulla. Reproductive structures in slightly broadened regions of terminal branchlets; tetrasporangia in sori, branchlets usually with conspicuous apical notch: cystocarps biloculate, subterminal, branchlets often with long, pointed distal extension.

Collections, ecology and regional distribution

Recorded from False Bay to just north of Durban (17-51) and from Namibia (Rull Lluch 2002). Found from the sublittoral fringe (usually at wave-exposed sites) to depths of at least 15 m.

World distribution: Southern African endemic.

Type locality: Palm Beach, near Port Edward, Kwazulu-Natal (Norris 1992).

Note: Previously recorded as Gelidium cartilagineum (L.) Gaillon and as G. versicolor (S.G. Gmelin) Lamouroux, species which also included the entity currently recognized as G. capense.

 

Gelidium pteridifolium, Kenton-on-Sea.

Gelidium pteridifolium.

Gelidium pteridifolium, showing branching pattern.

Gelidium pteridifolium, thallus apex. Reproduced from Stegenga et al. (1997).

 

References Gelidium pteridifolium

Norris RE 1992. The marine red algae of Natal, South Africa: Order Gelidiales (Rhodophyta). Memoirs of the Botanical Survey of South Africa 61: 43 pages.

Norris, R.E., Hommersand, M.H. and S. Fredericq 1987. Gelidium pteridifolium (Rhodophyceae), a new species from Natal and the eastern Cape. South African Journal of Botany 53: 375-380, 12 figs.

Rull Lluch, J. 2002. Marine benthic algae of Namibia. Scientia Marina 66 (Supplement 3): 258 pp.

Stegenga, H., Bolton, J.J. and R. J. Anderson. 1997. Seaweeds of the South African west coast. Contributions from the Bolus Herbarium 18: 655 pp.

 

Cite this record as:

Anderson RJ, Stegenga H, Bolton JJ. 2016. Seaweeds of the South African South Coast.
World Wide Web electronic publication, University of Cape Town, http://southafrseaweeds.uct.ac.za; Accessed on 23 November 2024.