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Electronic Flora of South Australia Family Fact Sheet
Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae
Thallus small, ecorticate, with prostrate indeterminate branches attached by multicellular rhizoids and erect, pinnate, indeterminate, but limited, branches, with the erect branches and rhizoids arising from a common cell of the prostrate filaments. Apical cells of the erect branches dividing transversely, subapical cells initiating first one and soon two opposite lateral branch lets, the lower cells of which form short, adaxial, filaments; gland cells absent. Cells uninucleate.
Reproduction: Gametophytes dioecious. Procarps borne on opposite branchlets which are shorter than the vegetative ones, with the fertile segment cutting off 1 or 2 periaxial cells, one (the supporting cell) bearing a 4-celled carpogonial branch plus a sterile cell which may produce a unicellular hair. Post-fertilization connection to the auxiliary cell occurs via a connecting cell and one to several gonimolobe initials are produced, with mature gonimolobes elongate, without any involucre. Spermatangia borne on short, opposite, branchlets, terminal on short cells.
Tetrasporangia terminal on the branchlets and their short adaxial branches, occasionally lateral on the cells, subspherical to ovoid, irregularly tetrahedrally divided.
Life history triphasic with isomorphic gametophytes and tetrasporophytes.
Type (and only) genus: Gymnothamnion J. Agardh 1892: 27, pl. 1 figs 11–14.
Taxonomic notes: Gymnothamnion when established was related to the Ptiloteae by J. Agardh, followed by Balakrishnan (1958) and Feldmann & Feldmann (1966). Moe & Silva (1979, p. 398) considered it was not a member of this tribe and Athanasiadis (1987, p. 68) assigned it to the Antithamnieae. It was placed in its own tribe by Kajumura (1989).
References:
AGARDH, J.G. (1892). Analecta Algologica. Acta Univ. lund. 28, 1–182, Plates 1–3.
ATHANASIADIS, A. (1987). A survey of the seaweeds of the Aegean Sea with taxonomic studies on the species of the tribe Antithamnieae (Rhodophyta). (University of Gothenburg, Department of Marine Botany.)
BALAKRISHNAN, M.S. (1958). Notes on Indian red algae. J. Indian Bot. Soc. 37, 138–146.
FELDMANN, J. & FELDMANN, G. (1966). Sur le Gymnothamnion elegans (Shousboe)J. Ag. et la situation des organes femelles chez les Céramiacées. Revue gén. Bot. 73, 5–17, Plate 1.
KAJIMURA, M. (1989). Gymnothamnieae trib. nov. (Ceramiaceae, Rhodophyta). Bot. Mar 32, 121–130.
MOE, R.L. & SILVA, P.C. (1979). Morphological and taxonomic studies on Antarctic Ceramiaceae (Rhodophyceae). I. Antarcticothamnion polysporum gen. et sp. nov. Br. phycol. J. 14, 385–405.
The Marine Benthic Flora of Southern Australia Part IIIC complete list of references.
Publication:
Womersley, H.B.S. (24 December, 1998)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIC. Ceramiales – Ceramiaceae, Dasyaceae
©State Herbarium of South Australia, Government of South Australia
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