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Order Erythropeltidales

Family Erythrotrichiaceae

Genus Erythrotrichia

Erythrotrichia welwitschii (Ruprecht) Batters 1902: 55

Thallus with branched uniseriate erect filament several mm long arising from an endophytic base without a disc; branching only in proximal to mid-region of thallus. Filaments uniformly 20-25 µm in diameter, cells longer than broad in proximal regions, usually broader than long in distal regions. Monospores formed by unequal division of vegetative cells. 

Collections, ecology and regional distribution 

Found as an epi- or endophyte on Ralfsia and some other brown algae. Recorded from Cape Point to Double Mouth, near Morgan Bay (17-43).

World distribution

Warm temperate European Atlantic, Namibia, Morocco, also recorded from California and Oregon (AlgaeBase).


  1. Further information on South African material of this species is found in Papenfuss (1952) and Stegenga et al (1997).
  2. An unnamed, similar species of Erythrotrichia (described from the west coast by Stegenga et al 1997: 218) has been found as far east as Keiskamma Point (Stegenga et al 2001). This entity has an endophytic base and emergent branched filament up to 3 mm long: it differs from welwitschii in that its multiseriate distal region becomes tubular and up to 100 µm in diameter.


Erythrotrichia welwitschii attached to fragment og brown algal host tissue

Erythrotrichia welwitschii,  detail of uniseriate upright filaments (fresh material), Nature’s Valley)

Erythrotrichia welwitschii, showing microscopic habit on the right and detail of a filament with monosporagnia on the left. This illustration reproduced from Stegenga et al. 1997.


References Erythrotrichia welwitschii

Batters, E.A.L. (1902). A catalogue of the British marine algae. Journal of Botany, British and Foreign 40 (Supplement): 1-107.

Papenfuss, G.F. (1952). Notes on South African marine algae III. Journal of South African Botany 17: 167-188.

Stegenga, H., Bolton, J.J. and R. J. Anderson. 1997. Seaweeds of the South African west coast. Contributions from the Bolus Herbarium 18: 640 pp.

Stegenga, H., Engledow, H.R., Bolton, J.J. & Anderson, R.J. (2001). The distribution of the family Erythropeltidaceae (Rhodophyta) along the temperate Southern African coast, with the description of Erythrotrichia platyphylla nov. spec. Nova Hedwigia 73(3-4): 367-379.


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.