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Order Ceramiales

Family Callithamniaceaae

Crouania attenuata (C. Agardh) J. Agardh 1842: 83

Plants up to ca. 1 cm tall, rather irregularly branched, but monopodial. Basal parts creeping, attached by multicellular rhizoids developed from the basal cells of the whorl branchlets. Main axis up to 120 µm across in the basal part. Indeterminate laterals given off at intervals of as few as four segments to more than fifteen. Each cell of the indeterminate axes with three whorl branchlets, these trichotomously branched basally, a few times dichotomously in the sections above and unbranched for the last 2-4 cells; branchlets standing out almost straight, slightly curved up in the apices, no obvious mucilage sheaths apparent, size up to ca. 100 µm long. Tetrasporangia sessile/adaxial on the basal cell of the branchlets, obovoid, measuring ca. 50(-60) x 45 µm, tetrahedrally divided. Sexual reproductive plants not seen.

Collections, ecology and regional distribution

Recorded from False Bay to Double Mouth (17-43); although known as a tropical species as well, we have not seen it in Transkei, possibly because it is not frequently found. It is collected as an epiphyte on Zonaria subarticulata, but also in turfs on non-living substrata.

World distribution: widespread in tropical areas throughout the world (Guiry & Guiry 2015).

Type locality: Brittany, France.


Crouania attenuata. 1. Habit. 2 Detail of axis with whorl branchlets. Reproduced from Stegenga et al. (1997).

Crouania attenuata. Thallus with tetrasporangia, Vleesbaai. Stained slide material.

Crouania attenuata. Thallus with tetrasporangia, detail. Stained slide material.


References Crouania attenuata

Agardh, J.G. 1842. Algae maris Mediterranei et Adriatici, observationes in diagnosin specierum et dispositionem generum. pp. [i]-x, 1-164. Parisiis [Paris]: Apud Fortin, Masson et Cie.

Guiry, M.D. & Guiry, G.M. 2015. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 26 November 2015.

Stegenga, H., Bolton, J.J. & 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 02 March 2024.