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Coeloclonium debile (Harvey) Gordon-Mills & Womersley 1987: 557

Phylum Rhodophyta – Family Rhodomelaceae – Tribe Chondrieae


Chondria debilis Harvey 1863, synop.: xix. De Toni 1903: 847; 1924: 383. De Toni & Forti 1923: 37 (in part). Guiler 1952: 104? Lucas 1909: 40; 1929a: 21(?). Lucas & Perrin 1947: 260.

Chondriopsis debilis (Harvey) J. Agardh 1892: 155. Sonder 1880: 34. Tisdal I 1898: 514. Wilson 1892: 168.

Thallus (Fig. 179A) red-brown, slender, 2–4 cm high, irregularly branched, branches basally constricted, 2–5 mm long and 0.5–1 mm in diameter, apices rounded and slightly depressed. Holdfast discoid, 0.5–1 mm across; epiphytic on Posidonia sinuosa and Dilophus. Structure. Apical filament short, bearing trichoblasts. Pericentral cells 5 (Fig. 179B), lengthening rapidly to form the broad branch apex, 20–40 (–100) µm in diameter and L/D (2–) 10–12, cortex 1 (–2) cells thick, outer cells ovoid to elongate, 20–35 µm in diameter and L/D 1–2 (–5), in longitudinal lines. Older axes with moderately abundant rhizoids (Fig. 179C) between the pericentral cells, cut off from these cells and their derivatives. Trichoblasts 300–700 µm long. Cells probably uninucleate; rhodoplasts discoid, chained in larger cells.

Reproduction: Procarps not observed. Carposporophytes with a small basal fusion cell and branched gonimoblast with clavate terminal carposporangia 40–120 µm in diameter. Cystocarps (Fig. 179D) ovoid, short-stalked, 1–1.5 mm in diameter; pericarp with a broad ostiole, ecorticate, 2 (–3) cells thick. Spermatangial plates not observed.

Tetrasporangia (Fig. 179E, F) borne on pericentral cells or their derivatives, one to few per whorl, 50–100 µm in diameter.

Type from King George Sound, W. Aust., on Posidonia (Harvey, Alg. Aust. Exsicc, 157B); lectotype in Herb. Harvey, TCD.

Selected specimens: Speeds Point, Sceale Bay, S. Aust., on Dilophus, 3–4 m deep (Edyvane, 30.ix.1982; AD, A53373). Tiparra Reef, S. Aust., on Posidonia sinuosa, 5 m deep (Shepherd, 19.v.1971; AD, A41317).

Distribution map based
on current data relating to
specimens held in the
State Herbarium of SA

Distribution: King George Sound, W. Aust., to Tiparra Reef, S. Australia.

Taxonomic notes: Coeloclonium debile is much smaller than the other species but agrees well in structure. It is apparently a rare species and further collections are desirable to clarify its structure.


AGARDH, J.G. (1892). Analecta Algologica. Acta Univ. lund. 28, 1–182, Plates 1–3.

DE TONI, G.B. & FORTI, A. (1923). Alghe di Australia, Tasmania e Nouva Zelanda. Mem. R. Inst. Veneto Sci., Lett. Arti 29, 1–183, Plates 1–10.

DE TONI, G.B. (1903). Sylloge Algarum omnium hucusque Cognitarum. Vol. 4. Florideae. Sect. 3. pp. 775–1521 + 1523–1525. (Padua.)

DE TONI, G.B. (1924). Sylloge Algarum omnium hucusque Cognitarum. Vol. 6. Florideae. (Padua.)

GORDON-MILLS, E.M. & WOMERSLEY, H.B.S. (1987). The genus Chondria C. Agardh (Rhodomelaceae, Rhodophyta) in southern Australia. Aust. J. Bot. 35, 477–565.

GUILER, E.R. (1952). The marine algae of Tasmania. Checklist with localities. Pap. Proc. R. Soc. Tasmania 86, 71–106.

HARVEY, W.H. (1863). Phycologia Australica. Vol. 5, Plates 241–300, synop., pp. i-lxxiii. (Reeve: London.)

LUCAS, A.H.S. & PERRIN, F. (1947). The Seaweeds of South Australia. Part 2. The Red Seaweeds. (Govt Printer: Adelaide.)

LUCAS, A.H.S. (1909). Revised list of the Fucoideae and Florideae of Australia. Proc. Linn. Soc. N.S.W. 34, 9–60.

LUCAS, A.H.S. (1929a). The marine algae of Tasmania. Pap. Proc. R. Soc. Tasm. 1928, 6–27.

SONDER, O.W. (1880). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

WILSON, J.B. (1892). Catalogue of algae collected at or near Port Phillip Heads and Western Port. Proc. R. Soc. Viet. 4, 157–190.

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.

Illustration in Womersley Part IIIA, 2003: FIG. 179.

Figure 179 image

Figure 179   enlarge

Fig. 179. Coeloclonium debile (A, D, AD, A41317; B, C, E, F, AD, A53373). A. Habit, on Posidonia. B. Transverse section of young branch. C. Transverse section of old branch. D. Cystocarp. E. Branch with tetrasporangia. F. Apex of tetrasporangial branch.

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