Electronic Flora of South Australia Genus Fact Sheet

Genus CHAMAETHAMNION Falkenberg in Schmitz & Falkenberg 1897: 449

Phylum Rhodophyta – Family Rhodomelaceae – Tribe Uncertain

Thallus epiphytic or parasitic on rhodomelaceous hosts, with a pseudoparenchymatous base and erect, simple or branched, branchlets 2–3 mm high, branchlets terete, with 5 pericentral cells and trichoblasts, ecorticate. Attachment by intermixing of parasite and host cells. Cells uninucleate; rhodoplasts absent or few.

Reproduction: Gametophytes dioecious. Procarps borne on a lower cell of trichoblasts, with a 4-celled carpogonial branch and sterile cells. Carposporophyte with a slight basal fusion cell and a branched gonimoblast with clavate carposporangia. Cystocarps ovoid, ostiolate, pericarp 2 cells thick, ecorticate. Spermatangial organs elongate-ovoid to subspherical.

Stichidia elongate, terete or compressed, bearing opposite tetrasporangia, with 2 cover cells.

Type species: C. schizandra Falkenberg in Schmitz & Falkenberg 1897: 449.

Taxonomic notes: Chamaethamnion contains the type species from Australia and a second species, C. pocockiae Norris (1988b, p. 346) from Natal. It is the only parasitic (or largely so), tufted, genus with ecorticate erect branches and stichidia with opposite tetrasporangia.

Kylin (1956, p. 496) placed Chamaethamnion in his Levringiella group of parasitic genera, while Hommersand (1963, pp. 337, 338) placed it in the Lophothalieae; however, the trichoblasts are not rhodoplastic as in the latter group, and it is here regarded as of uncertain position.

References:

HOMMERSAND, M.H. (1963). The morphology and classification of some Ceramiaceae and Rhodomelaceae. Univ. Calif. Pubis. Bot. 35(2), 165–366.

KYLIN, H. (1956). Die Gattungen der Rhodophyceen. (Gleerups: Lund.)

NORRIS, R.E. (1988b). Two new red algal parasites on Kuetzingia natalensis (Rhodomelaceae, Rhodophyta). Bot. Marina 31, 345–352.

SCHMITZ, F. & FALKENBERG, P. (1897). Rhodomelaceae. In Engler, A. & Prantl, K., Die natürlichen Pflanzenfamilien. T.1. Abt. 2, pp. 421–480. (Englemann: 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.

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