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Electronic Flora of South Australia Genus Fact Sheet
Phylum Rhodophyta – Family Rhodomelaceae – Tribe Lophothalieae
Thallus erect, radially branched, corticated, branches clothed with rhodoplastic, relatively persistent, trichoblasts, in some species also with adventitious monosiphonous filaments from the pericentral or cortical cells; holdfast discoid or fibrous. Structure monopodial, trichoblasts cut off from axial cells close to apices, with 5 to 7 pericentral cells developed in alternating sequence, clear or obscured in transverse section. Trichoblasts and adventitious filaments unbranched, slender. Cells multinucleate.
Reproduction: Gametophytes dioecious. Procarps developing on a lower cell of trichoblasts which becomes polysiphonous. Carposporophytes with a basal fusion cell and branched gonimoblast filaments with clavate terminal carposporangia. Cystocarps globular or urceolate, with or without a slight neck; pericarp ostiolate, usually not corticated. Spermatangial organs covering lower cells of trichoblasts with sterile basal and terminal cells.
Tetrasporangia formed in lesser branches, usually with trichoblasts, in decussate pairs each with 3 cover cells.
Type species: L. verticillata (Harvey) Kützing 1849: 797.
Taxonomic notes: Lophothalia was established as a subgenus of Dasya by Harvey (1847, p. 64) and elevated to genus by Kützing (1849, p. 797). It differs from Doxodasya essentially in the number of pericentral cells, 5–7 compared to 4 in the latter genus.
References:
HARVEY, W.H. (1847). Nereis Australis, pp. 1–69, Plates 1–25. (Reeve: London.)
KÜTZING, F.T. (1849). Species Algarum. (Leipzig.)
The Marine Benthic Flora of Southern Australia Part IIID complete list of references.
Publication:
Womersley, H.B.S. (24 February, 2003)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIID. Ceramiales – Delesseriaceae, Sarcomeniaceae, Rhodomelaceae
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIID 2003, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.
KEY TO SPECIES OF LOPHOTHALIA
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1. Trichoblasts more or less whorled on each segment, with frequent adventitious monosiphonous filaments from the cortex; pericentral cells 5, remaining clear in transverse section; trichoblasts | L. verticillata |
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1. Trichoblasts single from each segment, adventitious filaments absent or rare; branches usually infected with a hydroid (Halecium sp.); pericentral cells 6 or 7, becoming inconspicuous in transverse section of older branches; trichoblasts | L. hormoclados |
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Email Contact: State Herbarium of South Australia |
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