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Electronic Flora of South Australia Family Fact Sheet
Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae
Thallus erect, with or without a prostrate base, branches terete or compressed, with or without rhizoidal cortication. Axial cells with closely adjacent whorls of 3 or 4 whorl-branchlets formed in spiral or opposite sequence, branched several times; growth monopodial or with lower branches over-growing upper branches occasionally or repeatedly in a sympodial manner; lateral branches arising from basal cells of whorl-branches or (in Crouania and Gattya) from axial cells; gland cells absent or present on the whorl-branchlets, situated at an angle to the bearing cell and pit-connected to it.
Reproduction: Gametophytes dioecious. Procarps borne in place of whorl-branchlets or on the basal cell of whorl-branchlets, with apical growth ceasing after initiation, with a supporting cell bearing a 4-celled carpogonial branch; carposporophyte with terminal and lateral gonimolobes, surrounded by whorl-branchlets usually in rounded or clavate branch ends. Spermatangia terminal on cells of whorl-branchlets.
Tetrasporangia sessile on cells of whorl-branchlets, subspherical, tetrahedrally divided.
Life history triphasic with isomorphic gametophytes and tetrasporophytes.
Taxonomic notes: A tribe of 5 genera, all known from southern Australian coasts. Wollaston (1968, p. 402) divided the genera into two groups, dependent on the branching, whether there are 3 or 4 whorl-branchlets per axial cell, and the position of tetrasporangia on the whorl-branchlets.
References:
SCHMITZ, F. (1889). Systematische Ubersicht der bisher bekannten Gattungen der Florideen. Flora, Jena 72, 435–456, Plate 21.
WOLLASTON, E.M. (1968).Morphology and taxonomy of southern Australian genera of Crouanieae Schmitz (Ceramiaceae, Rhodophyta). Aust. J. Bot. 16, 217–417.
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 GENERA OF CROUANIEAE
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1. Whorl-branchlets in whorls of 3. Lateral branch initials arising on axial cells and basal cells of whorl-branchlets and forming a chain of | 2 |
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1. Whorl-branchlets in whorls of 4. Lateral branch initials arising on basal cells of whorl-branchlets and forming a chain | 3 |
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2. Axes of thallus terete. Axial branches (1 or 2) developed at irregular intervals unilaterally near branch apices | CROUANIA |
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2. Axes of thallus flattened. Axial branches developed singly, regularly and bilaterally forming pinnate thallus segments | GATTYA |
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3. Axes of thallus flattened with indeterminate and determinate branches alternately-distichously arranged | EUPTILOCLADIA |
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3. Axes of thallus terete with a more or less alternate-distichous arrangement of indeterminate lateral branches (irregular in Ptilocladia australis and Gulsonia); determinate short branches scattered irregularly over thallus (absent in P. australis) | 4 |
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4. Thallus spongiose and somewhat firm (flexuous in Ptilocladia australis).Branch initials | PTILOCLADIA |
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4. Thallus slimy-mucilaginous and flexuous. Branch initials | GULSONIA |
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