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Order Ceramiales

Family Spyridiaceae

Spyridia filamentosa (Wulfen) Harvey in Hooker 1833: 337

Plants (in South Africa) usually small, rarely reaching more than a few cm. Main axes distinct, lax, in vigorously growing parts with indeterminate laterals at intervals of 5-8 segments. Central cells slightly shorter to slightly longer than broad, producing some 13 periaxial cells, each with two derivatives that connect with the periaxials of the segments below. Primary periaxials and their immediate derivatives remaining exposed for a long time, at a later stage becoming covered with a secondary epidermis. Main axes to ca. 400 µm in diameter. Each segment with one determinate lateral up to about 15 segments long, laterals spirally arranged along the main axis. Central cells of the determinate laterals slightly shorter to slightly longer than broad, with an incomplete cortex, the branchlets reaching a length of 1 mm and a diameter of ca. 55 µm, provided with a single straight spine. Reproductive structures not seen in South African material.

Collections, ecology and regional distribution

Recorded from False Bay to northern KwaZulu-Natal (17-58). This species is not common in South Africa; found occasionally in rock pools, the sublittoral fringe or below. There appear to be no species of Spyridia on the west coast or the Namibian coast.

World distribution: one of the most widespread Spyridia species, occurring virtually world-wide in tropical to warm temperate sites.

Type locality: Adriatic Sea (Silva et al 1996).

Note: De Clerck et al. (2005) point out the resemblance of this species to Spyridia plumosa, which however lacks terminals pines on the determinate laterals.


Spyridia filamentosa, Goukou estuary, Stilbaai (fresh material, under dissecting microscope).

Spyridia filamentosa, microscopic habit, Preekstoel, near Stilbaai (stained slide).

Spyridia filamentosa, detail of main axis with short laterals (stained slide).

Spyridia filamentosa, thallus apex (stained slide).

Spyridia filamentosa, short laterals with single terminal spine (stained slide).


References Spyridia filamentosa

De Clerck, O, Tronchin, E. M., Schils, T. 2005. Red 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. 130-269.

Harvey, W.H. 1833. Div. II. Confervoideae; Div. III. Gloiocladeae. In: The English Flora of Sir James Edward Smith. Class XXIV. Cryptogamia. Vol. V. (or Vol. II of Dr. Hooker's British flora). Part I. Comprising the Mosses, Hepaticae, Lichens, Characeae and Algae. (Hooker, W.J. Eds), pp. 263-265, 265-266, 326-389, 389-405. London: Longman, Brown, Green & Longmans Paternoster-Row.

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.


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.