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Order Gracilariales

Family Gracilariaceae

Gracilaria denticulata F.Schmitz ex Mazza 1907: 138-139, Fig. 6

Plants purple to green, erect, firm-fleshy, strap-shaped, up to 17 cm tall, sparsely branched. Holdfast discoid to crustose, stipe terete, to 1 cm long. Blades irregularly sparsely branched, often with marginal proliferations or unbranched marginal laterals, up to 16 mm wide in middle, tapering distally, apices obtuse. Surfaces and margins of mature blades dentate or papillate, in young blades often smooth. Medullary cells up to 120 µm in diameter in middle of cross-section, decreasing in size towards the cortex, containing proteinaceaous crystals, transition from medulla to cortex abrupt in blades; cortex of 1-2 cell layers, cells pigmented, about 10 µm in diameter. Tetrasporangia evenly distributed in sori on both sides of blade, up to 25 x 35 µm, cruciately divided. Cystocarps evenly distributed on both blade surface, ostiolate, up to 1.6 mm high and 2 mm wide, constricted basally, pericarp to 30 cell layers thick, nutritive traversing cells common when mature.

Collections, ecology and regional distribution

Collected from Cannon Rocks to northern Kwazulu-Natal (38-58 ). Epilithic in the lower eulittoral and shallow sublittoral zones.

World distribution: Also recorded from Mozambique and reported from Mauritius, although there is some doubt about the latter record (De Clerk et al. 2005).

Type locality: “The Kowie” (Port Alfred), South Africa (Iyer et al. 2004).


Gracilaria denticulata, Mkambati (BOL).

Gracilaria denticulata (BOL).


References Gracilaria denticulata

De Clerck, O., J.J.Bolton, R. J. Anderson and E. Coppejans, 2005. Guide to the Seaweeds of Kwazulu-Natal. National Botanic Garden of Belgium, Brussels (Scripta Botanica Belgica), 294 pp.

Iyer, R., De Clerck, O, Bolton J.J. and V.E. Coyne. 2004. Morphological and taxonomic studies of Gracilaria and Gracilariopsis species (Gracilariales, Rhodophyta) from South Africa. South African Journal of Botany 70: 521-539.

Mazza, A. 1907 (1905-1918). Saggio di algologia oceanica. Nuova Notarisia 18: 1-36, 65-98, 126-152, 177-195.


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,; Accessed on 02 March 2024.