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Order Palmariales

Family Rhodothamniellaceae

Rhodothamniella floridula (Dillwyn) Feldmann in T.Christensen 1978: 67

Plants filamentous, caespitose, with an extensive system of prostrate filaments and a dense fur of erect filaments up to 30 mm high. Erect filaments sparingly branched, 19-25 µm in diameter, the cells 3-4 times as long as broad; cells with several (to 10) parietal, lobed chloroplasts, each with a central pyrenoid – in older cells apparently one chloroplast, the separate pyrenoids remaining visible. Tetrasporangia in small clusters, in uniseriate rows on the erect filaments; sporangia 30-35 (-40) x 25-30 (-35) µm, cruciately divided. Gametophytes only known from culture: small dioecious plants with a unicellular base. After fertilization the tetrasporophyte develops directly from the carpogonium/zygote; there is no development of a carposporophyte.

Collections, ecology and regional distribution

Recorded from Lamberts Bay on the west coast to Hluleka in the Transkei (9-45). Epilithic, forming turfs in the littoral zone, often sand-binding..

World distribution: Namibia, Atlantic Europe, Tristan da Cunha, Australia and Argentina (Kuipers in Guiry and Guiry, 2013).

Type locality: Galway Bay, Ireland (Silva et al., 1996).

Note: Stegenga (1985) describes South African specimens in detail, in his account of southern African Acrochaetiaceae, the family to which this species was formerly assigned.


Rhodothamniella floridula, stained microscope slide.

Rhodothamniella floridula, tetrasporangia.

Rhodothamniella floridula, vegetative cells with lobed, parietal chloroplasts.

Rhodothamniella floridula, 1. Microsopic habit. 2. Tetrasporangia. Reproduced from Stegenga et al. (1997).


References Rhodothamniella

Christensen, T. 1978. Annotations to a textbook of phycology. Botanisk Tidsskrift 73: 65-70.

Kuipers, P. in Guiry, M.D. & Guiry, G.M. 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 26 September 2013.

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. 1985. The marine Acrochaetiaceae (Rhodophyta) of southern Africa. South African Journal of Botany 51: 291-330.

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,; Accessed on 26 February 2024.