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Electronic Flora of South Australia Family Fact Sheet
Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae
Thallus with erect, slightly to moderately and irregularly branched filaments arising from prostrate filaments attached by haptera; cortication absent; gland cells absent. Cells multinucleate.
Reproduction: Gametophytes monoecious or dioecious. Procarps on the subapical cell of the female axis, enclosed in a gelatinous sheath together with associated sterile cells (one or two sterile periaxial cells, the apical cell and the sterile cell on the supporting cell) which remain undivided after fertilization in most genera (no inner involucre), but may divide to form small groups (Interthamnion) or a pericarp of erect filaments (Lejolisia). Auxiliary cells one or two per procarp, fusion cell present or absent, carposporangia terminal. An outer involucre of filaments on the hypogenous or subhypogenous cells present or absent. Spermatangia formed on compact heads.
Meiosporangia sessile or pedicellate on the erect filaments, tetrahedrally or polyhedrally divided (monosporangia absent).
Life history triphasic with isomorphic gametophytes and tetrasporophytes.
Taxonomic notes: The tribe Spermothamnieae includes some 9 genera. As well as the seven genera which occur on southern Australian coasts (see also Gordon 1972), Ptilothamnionopsis Dixon (1971, p. 61) occurs in California, and Gordoniella Itono (1977, p. 53) in Japan. Other genera previously placed in this tribe, but which produce 1–3-celled propagules, are now referred to the Monosporeae (Huisman & Gordon-Mills 1994).
This account is based very largely on that of Gordon 1972.
The following key is based entirely on female reproductive structures; many species can be identified only with doubt if only male or tetrasporangial thalli are present. Further studies of members of the tribe from other countries is necessary to support or modify the generic concepts developed by Gordon (1972) and others.
References:
DIXON, P.S. (1971). A study of Callithamnion lejolisea Farl. J. Phycol. 7, 58–63.
GORDON, E.M. (1972). Comparative morphology and taxonomy of the Wrangelieae, Sphondylothamnieae and Spermothamnieae (Ceramiaceae, Rhodophyta). Aust. J. Bot. suppl. 4, 1–180.
HUISMAN, J.M. & GORDON-MILLS, E.M. (1994). A proposal to resurrect the tribe Monosporeae Schmitz et Hauptfleisch, with a description of Tanakaella itonoi sp. nov. (Ceramiaceae, Rhodophyta) from southern and western Australia. Phycologia 33, 81–90.
ITONO, H. (1977). Studies on the Ceramiaceous algae (Rhodophyta) from southern parts of Japan. Bibliotheca Phycologia 35, 1–499.
SCHMITZ, F. (1889). Systematische Ubersicht der bisher bekannten Gattungen der Florideen. Flora, Jena 72, 435–456, Plate 21.
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 SPERMOTHAMNIEAE
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1. Carposporophyte with erect inner involucral filaments developing from sterile cells of the procarp; outer involucral filaments absent | 2 |
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1. Carposporophyte without inner involucral filaments from sterile cells of the procarp (except Interthamnion, with slight post-fertilization subdivision), but with or without outer involucral filaments arising from the hypogenous or subhypogenous cells | 3 |
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2. Inner involucral filaments forming a pericarp of associated filaments within a gelatinous sheath, with an apical ostiole | LEJOLISIA |
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2. Inner involucral filaments loosely arranged, not forming a pericarp within a gelatinous sheath | RHIPIDOTHAMNION |
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3. Carposporophyte without inner or outer involucral filaments | 4 |
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3. Carposporophyte with (Interthamnion) or without inner involucral filaments, with | 5 |
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4. Carposporophyte developing from 2 auxiliary cells per procarp; fusion cell prominent, T-shaped, involving the hypogenous cell | TIFFANIELLA |
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4. Carposporophyte developing from a single auxiliary cell; fusion cell absent | LOMATHAMNION |
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5. Carposporophyte developing from a single auxiliary cell; hypogenous cell much longer (L/D | PTILOTHAMNION |
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5. Carposporophyte developing from 2 auxiliary cells; hypogenous cell only slightly longer (L/D | 6 |
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6. Sterile procarp cells producing post-fertilization three small groups of | INTERTHAMNION |
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6. Sterile procarp cells not dividing; fusion cell prominent, incorporating the hypogenous cell; outer involucral filaments produced only from the subhypogenous cell | SPERMOTHAMNION |
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