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Order Dictyotales

Family Dictyotaceae

Padina boryana Thivy in W.R. Taylor 1966: 355, fig. 2

Plants light brown with white calcified layer on upper surface, comprising erect, curled, funnel-shaped blades, often split longitudinally; up to about 5 cm tall. Blade margin distinctively in-rolled, blades to about 2 cm diameter; stipe to 0.5 cm long, holdfast fibrous. Blade about 50 μm thick at apex, ca 190 μm thick near base; calcification on dorsal surface imparting concentric light whitish bands; darker bands in between resulting from hair rows on ventral blade surface. Blade of two cell layers above, three below; dorsal cells about twice as long as ventral cells. Sporangial sori borne on ventral surface in concentric rings just above hair bands, four spores per sporangium, indusium visible only in young blades. Gametophytes not seen.

Collections, ecology and regional distribution

Known from The Haven (some 150 km west of Port St Johns) to northern Kwazulu-Natal (44-58). Epilithic, typically on rocky ledges where there is some sand, from the mid eulittoral to shallow sublittoral zone.

World distribution: Mozambique, Tanzania, Kenya and worldwide in tropical and warm temperate localities (Guiry & Guiry 2012).

Type locality: Tonga Islands (Silva et al. 1996).

Note: Tronchin & De Clerck (2005) point out that this species can be confused with young specimens of Padina boergesenii Allender & Kraft, although blades of the latter may have up to four layers of cells. In South Africa P. boergesenii is only recorded north of Sodwana Bay.

 


Padina boryana, pressed specimen (BOL).


Padina boryana, XS of distal region of blade showing two cell layers.


Padina boryana, cross section of blade (slightly oblique) showing inrolled margin.


Padina boryana, LS through blade a few mm behind margin, showing three cell layers (stained slide preparation, Mkambati).

 

References Padina

Guiry, M.D. & Guiry, G.M. 2012. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched February 2012

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.

Taylor, W.R. (1966). Records of Asian and western Pacific marine algae, particularly algae from Indonesia and the Philippines. Pacific Science 20: 342-359, 2 text figs.

Tronchin, E. M., & De Clerck, O. 2005. Brown Algae. In: 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), pp. 96-129.

 

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 24 September 2018.