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Electronic Flora of South Australia Genus Fact Sheet
Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae – Tribe Sphondylothamnieae
Thallus erect, branching sparse to dense, main branches irregularly to alternately subdistichous. Whorl-branchlets 3 or 4 per axial cell, each pseudodi- to trichotomous, median cells 90–200 µm in diameter, terminal cells short and mucronate. Indeterminate branches arising on axial cells in addition to whorl-branchlets. Cortication when present by descending rhizoids from lower ends of axial cells, adhering by haptera with a terminal digitate disc. Cells multinucleate.
Reproduction: Gametophytes dioecious. Procarps subapical on short lateral axes with 4 smaller terminal and subterminal cells, the subapical cell bearing 2 sterile pericentral cells and a supporting cell with a terminal sterile cell and a lateral carpogonial branch. A single auxiliary cell produces a fusion cell with lobes bearing clavate carposporangia, surrounded by an inner involucre developed from the apical cell of the female axis, the 2 sterile pericentral cells and the sterile cell on the supporting cell. The hypogenous and subhypogenous cells do not bear laterals. Spermatangial heads are subspherical, borne on cells of villose whorl-branchlets.
Tetrasporangia borne on lower cells of modified whorl-branchlets just below the apices of short lateral branches, tetrahedrally divided.
Type species: W myriophylloides (Harvey) Gordon 1972: 89.
Taxonomic notes: A genus of 2 species on southern Australian coasts, distinguished by the 4 relatively small cells of the female axis with only the subapical cell producing pericentral cells, and the single auxiliary cell per procarp. Vegetative features are the formation of indeterminate branches in addition to whorl-branchlets on axial cells, the short mucronate cells terminating the whorl-branchlets, and the formation of haptera from the proximal ends of rhizoidal cells.
References:
GORDON, E.M. (1972). Comparative morphology and taxonomy of the Wrangelieae, Sphondylothamnieae and Spermothamnieae (Ceramiaceae, Rhodophyta). Aust. J. Bot. suppl. 4, 1–180.
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
KEY TO SPECIES OF WOLLASTONIELLA
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1. Branching of thallus and whorl-branchlets divergent; whorl-branchlets (3–) 4 per axial cell, branched | W. myriophylloides |
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1. Branching of thallus and whorl-branchlets fastigiate; whorl-branchlets 3 (–4) per axial cell, branched once or twice, median cells | W. mucronata |
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Email Contact: State Herbarium of South Australia |
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