Electronic Flora of South Australia Family Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales
Thallus erect, much branched with furcate terete branches or flat, calcified, internodal segments and uncalcified nodes. Structure multiaxial, with a dense filamentous medulla and a cortex of subspherical to ovoid cells in anticlinal rows.
Reproduction: Sexual organs in superficial nemathecia on upper branches or the flat segments, uncalcified. Carpogonial branches erect, several cells long, amongst multicellular paraphyses; auxiliary cells intercalary in nemathecial filaments, united by connecting filaments; carposporophytes lying between paraphyses, with most cells becoming carposporangia. Male nemathecia with tufts of spermatangia borne laterally on upper cells of paraphyses.
Tetrasporangia borne in outer cortex or in shallow nemathecia, elongate-ovoid, cruciately divided.
Life history triphasic with isomorphic gametophytes and tetrasporophytes.
Taxonomic notes: A family with two genera, Polyides (from the N. Atlantic) and Rhodopeltis, which Papenfuss (1966, p.251) transferred from the Cryptonemiales to the Gigartinales, on the basis that the auxiliary cell is "an undifferentiated intercalary cell of a nemathecial (vegetative) filament". However, the nemathecia are only formed associated with reproductive organs and are not strictly vegetative, and it seems best to place this family with the closely allied family Peyssonneliaceae.
KYLIN, H. (1956). Die Gattungen der Rhodophyceen. (Gleerups: Lund.)
PAPENFUSS, G.F. (1966). A review of the present system of classification of the Florideophyceae. Phycologia 5, 247–255.
The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.
Womersley, H.B.S. (14 January, 1994)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIA, Bangiophyceae and Florideophyceae (to Gigartinales)
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIA 1994, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.
State Herbarium of South Australia