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Order Ulotrichales

Family Ulotrichaceae

Ulothrix flacca (Dillwyn) Thuret in Le Jolis 1863: 56

Filaments attached by rhizoidal extensions from a few proximal cells, plants of rather indeterminate length. Growing by scattered intercalary divisions, at the same time the apical portion continually sloughing off in the process of spore formation. Filament diameter (10-) 12 -18 µm , the cells 0.2-1.0 times longer than broad, slightly longer in the proximal part. Cells with a single parietal girdle-shaped chloroplast and mostly one pyrenoid. Plants becoming reproductive in the distal part, sporangial (or gametangial) cells approximately isodiametric; forming 4-8 zooids.

Description from Stegenga et al. (1997).

Collections, ecology and regional distribution

Recorded from the west side of the Cape Peninsula to Knysna (16-30). Usually found in the supralittoral, also in brackish habitats. Epilithic and epiphytic.

World distribution: Widespread in temperate regions (Guiry & Guiry 2012).

Type locality: Swansea, Wales (Guiry & Guiry 2012).


Ulothrix flacca. 1. Part of basal filament. 2. Upper part of filament with zooidangia. Reproduced from Stegenga et al. (1997).


References Ulothrix

Guiry, M.D. & Guiry, G.M. 2012. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched September 2012.

Le Jolis, A. (1863). Liste des algues marines de Cherbourg. Mémoires de la Société Impériale des Sciences Naturelles de Cherbourg 10: 5-168, pls I-IV.

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.