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Electronic Flora of South Australia Family Fact Sheet
Phylum Rhodophyta – Family Rhodomelaceae
Thallus erect, irregularly radially branched, with or without divergent basal and upper parts, branches heavily corticated, terete or compressed, upper branches usually with prominent rhodoplastic trichoblasts. Structure monopodial, apical cells distinct, with 4 pericentral cells formed in alternating sequence and dividing longitudinally to form a ring of 7–8 cells around the axial cell, then cutting off outer cortical cells which show both longitudinal and transverse divisions; rhizoidal filaments developed abundantly from the inner cells, separating and obscuring the pericentral cells. Trichoblasts produced exogenously at apices from each segment, cells with abundant rhodoplasts.
Reproduction: Gametophytes dioecious. Procarps on lower trichoblast cells (usually the second) with the supporting cell bearing a 4-celled carpogonial branch and a single sterile group of 3 cells. Carposporophytes with a basal fusion cell, and branched gonimoblast with clavate terminal carposporangia. Cystocarps stalked to subsessile, ovoid, pericarp ostiolate, corticated, 4–5 cells thick. Spermatangial organs developed on branches of trichoblasts, with sterile apical cells, axial cells with 4 pericentral cells, cutting off initials which produce an outer layer of spermatangia.
Tetrasporangia in swollen branchlets bearing numerous trichoblasts, spirally arranged, single per segment, the stichidium corticated.
Type genus: Heterocladia Decaisne 1842: 359.
References:
DECAISNE, J. (1842). Essais sur une classification des Algues et des Polypiers calcifères de Lamouroux. Ann. Sci. Nat., 2 Sér. Bot., 17, 297–380, Plates 14–17.
FALKENBERG, P. (1901). Die Rhodomelaceen des Golfes von Neapel und der angrenzenden Meeres-abschnitte. Fauna und Flora des Golfes von Neapel. Monogr. 26. (Friedländer: Berlin.)
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.
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