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Electronic Flora of South Australia Species Fact Sheet

Rhodocallis elegans Kützing 1847: 36; 1849: 670; 1862: 17, pl. 57a-d.

Phylum Rhodophyta – Order Ceramiales – Family Ceramiaceae – Tribe Rhodocallideae

Selected citations: J. Agardh 1851: 101. De Toni 1903: 1373. Lucas 1909: 50; 1929a: 25. May 1965: 374. Hommersand et al. 1998: 865, figs 1–36.


Ptilota rhodocallis Harvey 1858: pl. 44; 1859b: 331. J. Agardh 1876: 79. Sonder 1881: 11.

Thallus (Fig. 168A) erect, medium to dark red and fading to carmine, 10–20 (–28) cm high, much branched complanately and pinnately with subdichotomous to irregular, terete to slightly compressed, main branches 400–800 µm broad, bearing regularly and closely arranged, distichous, compressed, simple determinate branchlets (1–) 2–4 mm long (Fig. 168B), with slight, spinous or blunt, marginal serrations on their upper half (especially on the abaxial edge). Holdfast rhizoidal, 2–10 mm across; epilithic. Structure. Apical cells (Fig. 168C) 10–12 µm in diameter and L/D 0.8–1, dividing by oblique alternate walls, each axial cell cutting off an initial periaxial cell, followed 1–2 axial cells lower by 2 more periaxial cells, then a fourth periaxial cell several axial cells below, formed in alternating sequence. The second and third formed periaxial filaments become transverse and are caducous (leaving only basal tissue) within a few mm of the apices, leaving the first formed filaments to form alternate, distichous, determinate laterals which become compressed, curved towards the branch apices, and have an apical spine and spines on the abaxial edges. Axial cells increasing to 120–180 µm in diameter and L/D 2–4 in the indeterminate axes; all branches becoming corticated by compacted filaments of short cells, arising from basal cells of the determinate laterals, with indeterminate branches producing rhizoidal filaments around the axial cells (Fig. 168D); these rhizoidal filaments extend out between the cortical cells close to the holdfast to form a hirsute surface coating. Lateral branches originate by continued growth of the apical cells of the distichous branchlets, with transition to spiral development. Cells uninucleate; rhodoplasts discoid in small cells, ribbon like in larger inner cells.

Reproduction: Gametophytes dioecious. Carpogonial branches occur in short series on successive axial cells of dwarf indeterminate axes, on the second and third formed periaxial cells which become the supporting cells, bearing 4-celled carpogonial branches, without sterile cells. Post-fertilization the supporting cell cuts off laterally an auxiliary cell, which, after nucleus transfer via a connecting tube, divides to form a foot cell and a gonimoblast initial, developing 3–6 gonimolobes each 400–600 µm across of ovoid carposporangia 20–30 µm in diameter. Rhizoidal involucral filaments arise from the basal cell of the sterile branchlet on the fertile axial cell and form a dense envelope around the developing carposporophyte, with the gonimolobes extending beyond the envelope at maturity; the carposporophyte (Fig. 168E) is also surrounded by incurved determinate branchlets. Spermatangia occur on the distichous branchlets and near the apices of indeterminate branches, with initials arising directly from outer cortical cells.

Tetrasporangia (Fig. 168F) occur on distichous branchlets near the tips of indeterminate axes, around the branchlets or in linear sori along the adaxial edges, developed directly from surface cortical cells, subspherical, 40–50 µm in diameter, tetrahedrally divided.

Type from "Neuholl and"(Herb. Binder); in Herb. Kützing, L, 941,253...292.

Selected specimens: St Francis I., Isles of St Francis, S. Aust., 55 m deep (Shepherd, 9.i.1971; AD, A38075). Pearson I., S. Aust., 22 m deep in shade (Shepherd, 12.i.1969; AD, A34026). 17 NM (about 34 km) S of Cape Willoughby, Kangaroo I., S. Aust., 45 m deep (Bone, 13.iii.1989; AD, A59851). Robe, S. Aust., drift (Womersley, 11.xii.1969; AD, A34863). 1.3 km off Cape Northumberland, S. Aust., 15 m deep (Shepherd, 13.ii.1976; AD, A55035) and 61m deep (Shepherd, 7.v.1975; AD, A46284). Warrnambool, Vic., drift (G. & J. Kraft, 30.ix.1994; MELU, K10366). Peterborough, Vic., drift (Pope & Bennett, 17.viii.1949; AD, Al2152). Port Phillip Heads, Vic. (Wilson, 1879; MEL, 26410) Eddystone Point, Tas., 30 m deep (Riddle, 24.ii.1990; AD, A60405). N end Governor I., Bicheno, Tas., 8–16 m deep (Edgar, 23.x.1994; AD, A63837). Stapleton Point, Prosser Bay, Tas., 12–15 m deep (Shepherd, 10.ii.1970; AD, A35771). Pirates Bay, Eaglehawk Neck, Tas., 9–12 m deep in kelp (Mitchell, 22.x.1994; AD, A64074). Cape Surville, Forestier Pen., Tas., 12 m deep (Goldsworthy, 28.ii.1990; AD, A60440). Fluted Cape, Bruny I., Tas., 16 m deep (Shepherd, 10.ii.1972; AD, A41530).

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

Distribution: Isles of St Francis, S. Aust., to Port Phillip Heads, Vic., and eastern Tasmania.

Taxonomic notes: R. elegans, described in detail by Hommersand et al. (1998), is a distinctive species found in deep water on rough-water coasts. There are superficial similarities with the type species of Euptilota, E. formosissima, from New Zealand, especially in general form and in the tetrasporangial sori, but seemingly they differ in apical development; the New Zealand species needs detailed study.


AGARDH, J.G. (1851). Species Genera et Ordines Algarum. Vol. 2, Part 1, I-XII, 1–336 + index. (Gleerup: Lund.)

AGARDH, J.G. (1876). Species Genera et Ordines Algarum. Vol. 3, Part 1- Epicrisis systematic Floridearum, pp. i-vii, 1–724. (Weigel: Leipzig.)

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

HARVEY, W.H. (1858). Phycologia Australica. Vol. 1, Plates 1–60. (Reeve: London.)

HARVEY, W.H. (1859b). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. III. Flora Tasmaniae. Vol. II, pp. 282–343, Plates 185–196. (Reeve: London.)

HOMMERSAND, M.H., WILSON, S.M. & KRAFT, G.T. (1998). Morphology and systematics of Rhodocallis elegans Kützing, Rhodocallideae, Trib. nov. (Ceramiaceae, Rhodophyta) from southeastern Australia. J. Phycol. 34, 865–879.

KÜTZING, F.T. (1847). Diagnosen and Bemerkungen zu neuen oder kritischen Algen. Bot. Zeit. 5, 1–5, 22–25, 33–38, 52–55, 164–167, 177–180, 193–198, 219–223.

KÜTZING, F.T. (1849). Species Algarum. (Leipzig.)

KÜTZING, F.T. (1862). Tabulae Phycologicae. Vol 12. (Nordhausen.)

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.

MAY, V. (1965). A census and key to the species of Rhodophyceae (red algae) recorded from Australia. Contr. N.S.W. natn. Herb. 3, 349–429.

SONDER, O.W. (1881). In Mueller, F., Fragmenta Phytographiae Australiae. Supplementum ad volumen undecinum: Algae Australianae hactenus cognitae, pp. 1–42, 105–107. (Melbourne.)

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (24 December, 1998)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIC. Ceramiales – Ceramiaceae, Dasyaceae
©State Herbarium of South Australia, Government of South Australia

Illustration in Womersley Part IIIA, 1998: FIG. 168.

Figure 168 image

Figure 168   enlarge

Fig. 168. Rhodocallis elegans (A, E, AD, A60405; B, AD, A35771; C, AD, A63837; D, AD, A64074; F, AD, A46284). A. Habit. B. Branch apex with distichous laterals from alternate axial cells. C. Apex with oblique divisions and alternate laterals. D. Transverse section of branch with extensive rhizoids around the axial filament. E. Branch with carposporophytes. F. Laterals with tetrasporangia borne on cortical cells.

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