|
|
|
|
|
|||||||||||
|
Electronic Flora of South Australia Family Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Corallinales – Family Corallinaceae
Thallus encrusting to warty, lumpy, fruticose, discoid, layered, foliose or arborescent, prostrate to erect; partially endophytic, epigenous or unattached and free-living as rhodoliths; genicula absent. Structure pseudoparenchymatous with monomerous or dimerous construction; cells of adjacent filaments joined by cell-fusions, secondary pit-connections unknown.
Reproduction: Vegetative reproduction by thallus fragmentation. Gametangia borne in uniporate conceptacles; tetrasporangia and bisporangia borne in multiporate conceptacles.
Gametangial thalli monoecious or dioecious; carpogonia and spermatangia produced in separate conceptacles or rarely in the same conceptacle. Carpogonial filaments mostly 2–4-celled, arising from the female conceptacle chamber floor. Carposporophytes developing within female conceptacles after karyogamy, composed of carposporangia terminating short gonimoblast filaments that arise from a central fusion cell or more commonly from an irregularly shaped fusion cell that may look discontinuous in section, or from a several-celled fusion cell complex, or without an evident fusion cell. Spermatangial filaments unbranched or branched, confined to the male conceptacle chamber floor or more commonly produced from both floor and roof.
Tetrasporangia and bisporangia borne on thalli separate from gametangia and carposporangia, with apical plugs each blocking a roof pore prior to spore release; tetrasporangia each containing four zonately arranged spores; bisporangia each containing two bispores. Conceptacle roofs formed from filaments interspersed amongst and peripheral to developing sporangia.
Type genus: Melobesia Lamouroux 1812: 186.
Taxonomic notes: The Melobesioideae includes nine genera, six of which (Lithothamnion, Mastophoropsis, Melobesia, Mesophyllum, Phymatolithon, Synarthrophyton) are represented in southern Australia. Clathromorphum (see Lebednik 1977b; Shepherd & Turner 1985, p. 288; Woelkerling 1988) is reported from various parts of the world but is not known from Australia (Woelkerling & Harvey 1993, p. 600); Exilicrusta (see Chamberlain 1992; Chamberlain & Irvine 1994c) is known only from the British Isles, and Kvaleya (see Adey & Sperapani 1971; South & Talley 1986; Woelkerling 1988) is known from various localities in the boreal Atlantic and Arctic. Sporolithon, formerly placed by many authors (see Woelkerling & Townsend 1988, p. 203) in the Melobesioideae, is now referred to a separate family, the Sporolithaceae. Leptophytum, recognised by some authors, is considered in need of further evaluation (Woelkerling 1988, p. 217; Wilks & Woelkerling 1994, pp. 199–201). The Lithothamnioideae Foslie (1908: 19) is a heterotypic synonym of the Melobesioideae, while the Nulliporoideae Harvey (1849: 94) is an illegitimate older name (see Woelkerling 1988, p. 158).
Note on key: The use of spermatangial characters to delimit Synarthrophyton from Mesophyllum is discussed by Harvey et al. (1994, pp. 340–341). Because tetrasporangial or bisporangial plants are more commonly found than male plants in southern Australia, the following supplementary tabular key is provided for the identification of the five southern representatives of these genera (4 species of Mesophyllum; one of Synarthrophyton). Further comments on identifying Mesophyllum engelhartii and Synarthrophyton patena are provided in the accounts of those species.
Supplementary tabular key to southern Australian species of Mesophyllum and Synarthrophyton. T/B = tetrasporangial/bisporangial. Characters are depicted in figures accompanying each species account.
| | TB CONCEPTACLE ROOF | T/B CONCEPTACLE PORE CANALS | SPERMATANGIAL FILAMENTS |
| Mesophyllum engelhartii (Figs 82, 83) | not differentiated into a peripheral rim and a central sunken pore-plate | pore canals bordered by cells similar in size and shape to other roof cells above chamber | simple |
| Mesophyllum incisum (Figs 84, 85) | not differentiated into a peripheral rim and a central sunken pore-plate | pore canals bordered by cells that are narrower and more elongate than adjacent roof cells | simple |
| Mesophyllum macroblastum (Figs 86, 87) | differentiated into a peripheral rim and a central sunken pore-plate | pore canals bordered by cells similar in size and shape to other roof cells above chamber | simple |
| Mesophyllum printzianum (Figs 88, 89) | >differentiated into a peripheral rim and a central sunken pore-plate | pore canals bordered by cells that are narrower and more elongate than adjacent roof cells | simple |
| Synarthrophyton patena (Figs 90, 91) | not differentiated into a peripheral rim and a central sunken pore-plate | pore canals bordered by cells similar in size and shape to other roof cells above chamber | branched |
References:
ADEY, W.H. & SPERAPANI, C.P. (1971). The biology of Kvaleya epilaeve, a new parasitic genus and species of Corallinaceae. Phycologia 10, 29–42.
BIZZOZERO, G. (1885). Flora Veneta Crittogamica. Part 2. (Seminario: Padova.)
CHAMBERLAIN, Y.M. & IRVINE, L.M. (1994c). Melobesioideaae Bizzozero. In Irvine, L. M. & Chamberlain, Y. M. (Eds), Seaweeds of the British Isles. Volume 1 Rhodophyta Part 2B Corallinales, Hildenbrandiales pp. 159–234. (HMSO: London.)
CHAMBERLAIN, Y.M. (1992). Observations on two melobesioid crustose coralline red algal species from the British Isles: Exilicrusta parva, a new genus and species, and Lithothamnion sonderi Hauck. Br. phycol. J. 27, 185–201.
FOSLIE, M. (1908). Algologiske notiser. V. K. norske Vidensk. Selsk. Skr. 1908(7), 1–20.
HARVEY, A.S., WOELKERLING, W.J. & WILKS, K.M. (1994). The genus Synarthrophyton (Corallinaceae, Rhodophyta) in southern Australia. Phycologia 33, 331–342.
LAMOUROUX, J.V.F. (1812). Sur la classification des Polypiers coralligenès non entièrement pierreux. Nouv. Bull. Sci. Soc. Philom. Paris 3, 181–188.
LEBEDNIK, P.A. (1977b). The Corallinaceae of northwestern North America. I. Clathromorphum Foslie emend. Adey. Syesis 9, 59–112.
SHEPHERD, S.A. & TURNER, J.A. (1985). Studies on southern Australian abalone (genus Haliotis). VI. Habitat preference, abundance and predators of juveniles. J. exp. mar. Biol. Ecol. 93, 285–298.
WILKS, K.M. & WOELKERLING, W.J. (1994). An account of southern Australian species of Phymatolithon (Corallinaceae, Rhodophyta) with comments on Leptophytum. Aust. Syst. Bot. 7, 183–223.
WOELKERLING, W.J. & HARVEY, A. (1993). An account of sourthern Australian species of Mesophyllum (Corallinaceae, Rhodophyta). Aust. Syst. Bot. 6, 571–637.
WOELKERLING, W.J. & TOWNSEND, R.A. (1988). Sporolithon Heydrich. In Woelkerling, W.J. (Ed.), The Coralline Red Algae: An Analysis of the Genera and Subfamilies of Nongeniculate Corallinaceae pp. 203–210. (British Museum (Natural History) and Oxford University Press: London and Oxford.)
WOELKERLING, Wm.J. (1988). The Coralline Red Algae. [British Museum (N.H.): London.]
The Marine Benthic Flora of Southern Australia Part IIIB complete list of references.
Publication:
Womersley, H.B.S. (28 June, 1996)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIB. Gracilarialse, Rhodymeniales, Corallinales and Bonnemaisoniales
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIB 1996, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.
KEY TO GENERA OF MELOBESIOIDEAE
|
1. Thallus construction dimerous (Figs 69C, 71C); consisting of two distinct groups of laterally cohering filaments/cells: a ventral unistratose layer of filaments each composed of palisade or non-palisade cells and secondly epithallial cells or multicellular filaments arising more or less perpendicularly from cells of the ventral-most layer | MELOBESIA |
|
1. Thallus construction monomerous (Fig. 62A, B); consisting of a single system of branched, laterally cohering, filaments that contribute to a ventrally or centrally situated core and a peripheral region where portions of filaments curve outwards towards the thallus surface | 2 |
|
2. Thalli arborescent (Fig. 73A), composed of flattened, branched, flexible, ribbon like ascending or erect axes that arise from a distinct holdfast and a compressed to flattened stipe | MASTOPHOROPSIS |
|
2. Thalli encrusting, warty, lumpy, fruticose, discoid, layered and/or foliose; not producing ribbon like branches, stipes and holdfasts | 3 |
|
3. Distal walls of terminal epithallial cells flattened and flared (Fig. 63C) | LITHOTHAMNION |
|
3. Distal walls of terminal epithallial cells rounded or flattened but not flared (Fig. 63A, B) | 4 |
|
4. Subepithallial initials as short as or shorter than the cells immediately subtending them (Fig. 63A); tetrasporangial and bisporangial conceptacles arising adventitiously from groups of vegetative cells within the thallus (Figs 78E, 80E) | PHYMATOLITHON |
|
4. Subepithallial initials as long or longer than the cells immediately subtending them (Fig. 63B); tetrasporangial and bisporangial conceptacles arising directly from groups of subepithallial initials (Figs 86C, 89A) | 5 |
|
5. Male conceptacles with only unbranched spermatangial filaments (Figs 83D, 85D) | MESOPHYLLUM |
|
5. Male conceptacles with mostly branched spermatangial filaments (Fig. 91C) | SYNARTHROPHYTON |
|
Email Contact: State Herbarium of South Australia |
|
