Electronic Flora of South Australia Genus Fact Sheet

Genus SARCOMENIA Sonder 1845: 56.

Phylum Rhodophyta – Family Sarcomeniaceae

Thallus much branched with flat axes and laterals arising between midrib and margins, more or less linear, tapering to acute apices, decomposing rapidly on death; holdfast fibrous. Structure. Apical cell hemispherical, axial cells cutting off first an abaxial transverse pericentral cell, then 2 lateral pericentral cells, followed by the adaxial transverse pericentral cell. Lateral pericentral cells forming 2 flanking cells, the upper cutting off 2 cells and each of these 3 cells developing a row of cells to form the flat blades, with the whole blade becoming corticated. Lateral branches arise endogenously from the axial cells and become displaced to between the midrib and margin. Cells uni- to multinucleate.

Reproduction: Gametophytes dioecious. Procarps on the adaxial transverse pericentral cells which form the supporting cell, cutting off a sterile cell then the 4-celled carpogonial branch, followed by a second lateral sterile cell. Carposporophyte with a basal, erect, fusion cell and much branched gonimoblast bearing terminal carposporangia. Cystocarps ovoid to urceolate, pedicellate; pericarp ostiolate, of erect filaments with each cell cutting off 2 cells outwardly, the wall becoming 3–4 cells thick. Spermatangial blades developed laterally on older blades, with the lateral pericentral and outer cells producing a plate of initials which cut off elongate spermatangia, covering most of the blade except for transverse pericentral cells and marginal (or near) cells.

Tetrasporangial blades single or clustered, originating from axial cells, with the lateral pericentral cell derivatives only dividing horizontally to form protective, curved, marginal cells; lateral pericentral cells each cutting off a tetrasporangium followed by 2 cover cells, so that the blade bears 2 rows of tetrasporangia, maturing basally.

Type species: S. delesserioides Sonder 1845: 56.

Taxonomic notes: Sarcomenia contains only a single species.

References:

SONDER, O.G. (1845). Nova Algarum genera et species, quas in itinere ad oras occidentales Novae Hollandiae, collegit L. Preiss, Ph.Dr. Bot. Zeit. 3, 49–57.

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

Publication: Womersley, H.B.S. (24 February, 2003)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIID. Ceramiales – Delesseriaceae, Sarcomeniaceae, Rhodomelaceae
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIID 2003, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

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