Electronic Flora of South Australia Genus Fact Sheet

Genus TREMATOCARPUS Kützing 1843: 410

Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Sarcodiaceae

Thallus terete to compressed, narrow, subdichotomously branched with linear branches and rounded axils and apices, firm and cartilaginous. Structure multiaxial, with a dense medulla of longitudinal filaments of long cells and a pseudoparenchymatous cortex of ovoid cells, smaller outwardly.

Reproduction: Sexual thalli usually dioecious. Carpogonial branches 3-celled, borne on intercalary cortical cells, often reflexed but with the trichogyne outwardly directed; supporting cell acting as the auxiliary cell. Carposporophyte with a basal reticulum of partly fused cells with erect gonimoblast filaments producing short terminal chains of carposporangia. Cystocarps protuberant, ostiolate, with a thick pericarp. Spermatangia in sori near tips of branches, cut off from surface cortical cells.

Tetrasporophytes with nemathecia on upper branches, tetrasporangia lying between anticlinal filaments, zonately divided.

Life history triphasic with isomorphic gametophytes and tetrasporophytes.

Lectotype species: T. dichotomus Kützing 1843: 410.

Taxonomic notes: A genus of about 5 species from South Africa, the South Pacific Ocean and Japan.

Searles (1969) showed that Dicurella Harvey ex J. Agardh (1852, p. 629), which had been studied by Searles (1968, p. 69), should be considered a synonym of Trematocarpus. The latter genus differs from Sarcodia in its narrow, slightly compressed branches and in the compact medulla of longitudinal, long-celled, filaments which form a core of slightly smaller cells in transverse section, not the entangled filaments of Sarcodia. T. acicularis (J. Agardh) Kylin from New Zealand, however, has a medulla of entangled filaments and also differs in form from the type and other species of Trematocarpus.

References:

AGARDH, J.G. (1852). Species Genera et Ordines Algarum. Vol. 2, Part 2, pp. 337–720. (Gleerup: Lund.)

KÜTZING, F.T. (1843). Phycologia generalis. (Leipzig.)

SEARLES, R.B. (1968). Morphological studies of red algae of the order Gigartinales. Univ. Calif Pubis Bot. 43, vi + 1–86, Plates 1–12.

SEARLES, R.B. (1969). Observations on the morphology of Trematocarpus dichotomus Kützing and the status of the genus Dicurella. Phycologia 8, 21–25.

The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.

Author: H.B.S. Womersley

Publication: 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.

KEY TO SPECIES OF TREMATOCARPUS

1. Branches strongly compressed, 1–2 mm broad

T. affinis


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