Electronic Flora of South Australia Genus Fact Sheet

Genus CLADURUS Falkenberg in Schmitz & Falkenberg 1897: 435

Phylum Rhodophyta – Family Rhodomelaceae – Tribe Chondrieae

Thallus erect, robust, irregularly radially branched; holdfast conical to divided. Structure. Apical cell surmounting a short, slender apex, with trichoblasts, then broadening suddenly by enlargement of pericentral cells; 5 (–6) pericentral cells, becoming relatively large and remaining conspicuous throughout the thallus, surrounded by a narrow single-celled cortex, later several cells thick; face view of branches showing clear segments corresponding to the tiers of pericentral cells; rhizoids surround the older axial and pericentral cells.

Reproduction: Gametophytes dioecious. Procarps probably borne on trichoblasts. Carposporophytes with a prominent, branched, fusion cell and branched gonimoblast with terminal carposporangia. Cystocarps borne on short axillary branchlets, ovoid, pericarp corticated, several cells thick. Spermatangial organs on branches of trichoblasts, terete and elongate.

Tetrasporangial stichidia in axils of lateral branches, elongate, corticated, tetrasporangia spirally arranged, cut off from pericentral cells.

Type (and only) species: C. elatus (Sonder) Falkenberg in Schmitz & Falkenberg 1897: 435.

Taxonomic notes: The name Cladurus was first used by Schmitz (1889, p. 448), credited to Falkenberg but without description.

Cladurus is distinguished by the relatively very large pericentral cells, compactly arranged with only a thin cortex; in face view the branches show clear segments corresponding to each tier of pericentral cells. The terete spermatangial organs, distinctly different to the plate-like organs of the Chondrieae, show that Cladurus is not a member of the Chondrieae (see Gordon Mills & Womersley 1987, p. 561), but its placement is uncertain and may be clarified by sequencing studies.

References:

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

SCHMITZ, F. (1889). Systematische Übersicht der bisher bekannten Gattungen der Florideen. Flora, Jena 72, 435–456, Plate 21.

WOMERSLEY, H.B.S. (1987). The Marine Benthic Flora of southern Australia. Part II. (Govt Printer: Adelaide.)

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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