Electronic Flora of South Australia Species Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Gigartinales – Family Areschougiaceae
Selected citations: J. Agardh 1876: 278. Kylin 1932: 36. Lucas & Perrin 1947: 169. Min-Thein & Womersley 1976: 84, fig. 61A.
Rhabdonia (?) sonderi J. Agardh sensu Harvey 1855a: 554.
Thallus (Fig. 115F) medium to dark red, (5–) 10–15 cm high, much branched with clavate to elongate-ovoid segments (4–) 6–10 (–20) mm long and (1.5–) 2–3 (–4) mm in diameter, markedly constricted, with 2–4 (–7) branches from segment apices; lower branches becoming thickened (1–2 mm) and terete, though original segments usually still indicated. Holdfast discoid, 2–7 mm across, with 1–4 axes; epilithic. Structure uniaxial, with each axial cell producing two periaxial filaments at about 90°, alternating on successive cells, with rhizoids surrounding the conspicuous axial filament; medulla lax in upper segments, becoming filled with rhizoids in thickened branches. Cortex pseudoparenchymatous, 2–3 (–4) cells thick, inner cells ovoid and 20–30 µm in diameter, outer cells 6–14 µm in diameter, L/D 1–1.5, in thickened parts forming files 6–12 cells long. Rhodoplasts discoid to ribbon shaped, several per cell.
Reproduction: Carpogonial branches 3-celled, borne on inner cortical cells, directed inwards with reflexed trichogynes. Connecting filaments and auxiliary cells not observed. Carposporophytes with a central fusion cell and radiating gonimoblasts with terminal chains of ovoid carposporangia 20–25 µm in diameter. Cystocarps (Fig. 115G) lying within the medulla, with filamentous enveloping tissue, slightly swelling the segment, ostiolate. Spermatangia unknown.
Tetrasporangia scattered in the cortex, developed from inner cortical cells and pit-connected laterally, protruding markedly into the medulla, ovoid, 150–175 µm long and 65–90 µm in diameter, zonately divided.
Type from Fremantle, W. Aust., (Clifton); holotype (Tray. set 139) in TCD.
Selected specimens: Dongara, W. Aust., 3 m deep (Borowitzka, 22.iv.1979; AD, A52489). Hamelin Bay, W. Aust., drift (Royce 762, 21.vi.1950; AD, A15501). Semaphore, S. Aust., 24 m deep (Shepherd, 28.xii.1968; AD, A33325). Vivonne Bay, Kangaroo I., S. Aust., drift (Womersley, 14.i.1948; AD, A6902). 35 km NW of Robe, S. Aust., 40 m deep (Shepherd, 20.xi.1968; AD, A33101). Currie R. mouth, N Tas. (Perrin, Jan. 1938; MEL, 44758).
Distribution: Dongara, W. Aust., to Robe, S. Aust., and the N coast of Tasmania.
Taxonomic notes: Harvey (1855a, p. 554) first ascribed this species to J. Agardh's Rhabdonia ? sonderi, which is a synonym of Coeloclonium opuntioides (Harvey) J. Agardh.
AGARDH, J.G. (1876). Species Genera et Ordines Algarum. Vol. 3, Part 1 - Epicrisis systematis Floridearum, pp. i-vii, 1–724. (Weigel: Leipzig.)
HARVEY, W.H. (1855a). Some account of the marine botany of the colony of Western Australia. Trans. R. Ir. Acad. 22, 525–566.
HARVEY, W.H. (1859a). Phycologia Australica. Vol. 2, Plates 61–120. (Reeve: London.)
KYLIN, H. (1932). Die Florideenordnung Gigartinales. Lunds Univ. Årsskr. N.F. Avd. 2, 28 (8), 1–88, Plates 1–28.
LUCAS, A.H.S. & PERRIN, F. (1947). The Seaweeds of South Australia. Part 2. The Red Seaweeds. (Govt Printer: Adelaide.)
MIN-THEIN, U. & WOMERSLEY, H.B.S. (1976). Studies on southern Australian taxa of Solieriaceae, Rhabdoniaceae and Rhodophyllidaceae (Rhodophyta). Aust. J. Bot. 24, 1–166.
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.
Illustration in Womersley Part IIIA, 1994: FIG. 115F, C.
Figure 115 enlarge
Fig. 115. A. Erythroclonium muelleri (AD, A46348). Habit. B–D. Erythroclonium sedoides [B, C, UWA, A1339 (AD, A44584); D, AD, A11926]. B. Habit. C. Transverse section of older branch. D. Section of cortex with tetrasporangia. E. Erythroclonium angustatum (AD, A43965). Habit. F, G. Erythroclonium sonderi (F, AD, A33101; G, AD, A52489). F. Habit. G. Section of cystocarp. [B as in Min-Thein & Womersley 1976.]
State Herbarium of South Australia