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Genus LOMATHAMNION Gordon 1972: 125

Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae – Tribe Spermothamnieae

Thallus tufted and spreading, with prostrate filaments attached by digitate haptera, and erect, simple to sparingly branched, uniseriate erect filaments; epiphytic on Codium. Cells multinucleate.

Reproduction: Gametophytes dioecious. Procarps subapical on short lateral branches, the last 3 cells shorter, with 2 periaxial cells, one sterile and the other (supporting) cell bearing a sterile apical cell and a lateral carpogonial branch; the single auxiliary cell divides post-fertilization to produce short gonimoblast filaments with terminal ovoid carposporangia, the 2–4 gonimolobes each with a gelatinous sheath; fusion cell absent; inner and outer involucra] filaments absent. Spermatangial heads ovoid, borne on unicellular pedicels on the erect or prostrate filaments.

Tetrasporangia are terminal on unicellular pedicels, lateral on the erect filaments, tetrahedrally divided, often appearing cruciate.

Type species: L. epicodii Gordon 1972: 127.

Taxonomic notes: A genus of 2 species, the type and L. capense Stegenga (1984, p. 357) from South Africa.

Lomathamnion is distinct from other genera of the tribe in having only 2 periaxial cells, as well as having only a single auxiliary cell, lacking a fusion cell, and lacking inner and outer involucres around the carposporophyte.


GORDON, E.M. (1972). Comparative morphology and taxonomy of the Wrangelieae, Sphondylothamnieae and Spermothamnieae (Ceramiaceae, Rhodophyta). Aust. J. Bot. suppl. 4, 1–180.

STEGENGA, H. (1984). A new species of Lomathamnion (Rhodophyta, Ceramiaceae) from South Africa. South African J. Bot. 3, 351–355.

The Marine Benthic Flora of Southern Australia Part IIIC complete list of references.

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (24 December, 1998)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIC. Ceramiales – Ceramiaceae, Dasyaceae
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