Seaweeds of the South African South Coast

 

 

 

 

 

 

 

 

 

 

 

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Dictyotales

Dictyotaceae

Dictyopteris ligulata (Suhr) O.C.Schmidt 1938: 219

Plants brown to yellowish-brown, up to 30 cm tall, blades strap-shaped, subdichotomously branched, with lighter coloured midrib and smooth margins; holdfast a mat of rhizoids. Blades 1-1.5 cm wide throughout, midrib ca. 3 mm wide; blade wings ca. 200 µm thick, midrib ca. 400 µm thick. Hairs in tufts, forming obliquely-oriented lines from midrib towards margins. Cortex a single layer of densely pigmented cells 15-18 µm deep x 10-13 µm wide. Medulla up to 6 cells deep in outer wings of blade, up to 14 cells deep in midrib. Medullary cells in obvious rows, variable in shape from polygonal to elongated, smaller near thallus edge. Sporangia ca. 100 µm in diameter, dividing tetrahedrally when mature; in sori on both sides of midrib, almost completely embedded in cortex. Gametangia not seen.

Collections, ecology and regional distribution

Common in the lower eulittoral and shallow subtidal zones. Recorded from the Cape Agulhas region to Black Rock in northern Kwazulu-Natal (22-58).

World distribution: southern African endemic.

Type locality: Algoa Bay (Silva et al. 1996).

Note: Stegenga et al. (1997) considered that D. ligulata was the correct name for the species known as D. longifolia (Papenfuss, nom. inval.). Nevertheless there may be more species of Dictyopteris present on the South Coast and this group needs re-investigation in South Africa.

 

Dictyopteris ligulata, Port Alfred, showing characteristic markings.

Dictyopteris ligulata (herbarium specimen, Dome Bluff, Transkei).

 

References Dictyopteris ligulata

Schmidt, O.C. (1938). Beiträge zur Systematik der Phaeophyten I. Hedwigia 77: 213-230.

Silva, P.C., Basson, P.W. & Moe, R.L. (1996). Catalogue of the benthic marine algae of the Indian Ocean. University of California Publications in Botany 79: 1-1259.

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 18 November 2024.