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Order Ceramiales

Family Ceramiaceae

Antithamnionella tormentosa Stegenga 1986: 48, pl. 13

Plants partly creeping, attached by up to three rhizoids from the proximal cells of up to three branchlets or indeterminate laterals, sometimes developed into haptera. Erect parts to 2.5 mm tall (much larger in the type from the Western Cape), with four or five laterals including an indeterminate lateral every second segment (on creeping filaments every segment may bear an indeterminate branch). Determinate laterals variable (within a single whorl), from unbranched to provided with a short series of adaxial branchlets. Main axis to 60 µm in diameter, the cells to 170 µm long. Determinate laterals to 12 cells long, with an acute apex. Gland cells on the fourth to seventh cell, ca. 20 µm in largest diameter. Tetrasporangia sessile or stipitate, on second to fourth cell of the determinate branchlets, 50x30 µm, cruciately to tetrahedrally divided. Spermatangial stands four- or five-celled, rather straight, on all but the terminal 2-4 cells of the determinate branchlets. Up to 3 or 4 spermatangial stands per cell. Female structures not known.

Collections, ecology and regional distribution

Rare on the south coast; recorded from the Cape Peninsula to Tsitsikamma (16-32). In the Western Cape known from a number of algal substrata, and from Pyura stolonifera. The reported larger plants (Stegenga et al. 1997) were apparently only collected by Pocock.

World distribution: A South African endemic.

Type locality: Oudekraal, Cape Peninsula, Western Cape Province, South Africa (Stegenga 1986).


Antithamnionella tormentosa. 1. Part of prostrate axis with determinate branchlets. 2. Detail of erect axis with tetrasporangia. Reproduced from Stegenga et al. (1997).

Antithamnionella tormentosa. Tetrasporangial thallus, Tsitsikamma. Stained slide.

Antithamnionella tormentosa. Male thallus, Tsitsikamma. Stained slide.


References Antithamnionella tormentosa

Stegenga, H. 1986. The Ceramiaceae (excl. Ceramium) (Rhodophyta) of the South West Cape Province, South Africa. Bibliotheca Phycologica 74: 1-149, 1 table, 51 plates.

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.