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Electronic Flora of South Australia Species Fact Sheet

Ptilonia australasica Harvey 1859b: 305, pl. 190A.

Phylum Rhodophyta – Class Florideophyceae – Order Bonnemaisoniales – Family Bonnemaisoniaceae

Selected citations: J. Agardh 1876: 674. De Toni 1900b: 759. Guiler 1952: 85. Levring 1953: 516, figs 44, 45B–E. Lucas 1929a: 20. Lucas & Perrin 1947: 240, fig. 102. May 1965: 398. Reinbold 1898: 48. Sonder 1881: 30. Tisdall 1898: 512. Wilson 1892: 169.


Delisea australasica (Harvey) Chihara ex Chihara & Yoshizaki 1978: 387.

Thallus (Fig. 158A) medium red to dark red-brown, 10–30 cm high, essentially complanately and alternately marginally branched, axils rounded, apices obtuse; branches (1–) 2–4 (–5) mm broad, entire, often slightly basally constricted, older parts usually denuded. Holdfast discoid to lobed, 3–6 mm across, with one to several fronds; epilithic. Structure (Fig. 158B–D) uniaxial, apical cell inconspicuous, lateral periaxial filaments alternately longer and shorter on successive axial cells, axial filament prominent (Fig. 158C, D), becoming 60–90 (–200) µm in diameter, with a sheath of rounded to elongate rhizoidal cells; cortex compact, inner cells subspherical to ovoid, (25–) 50–100 µm in diameter, with intermixed smaller cells, outermost cortical cells 2–5 µm in diameter and L/D 1–2 in thallus section, with scattered larger, clear, gland cells in or just under the outer layer. Older axes with a secondary meristem (Fig. 158C), developing files of small cells from outer cortical cells, forming a midrib. Rhodoplasts discoid in outer cells, becoming ribbon like and branched in inner cells.

Reproduction: Gametangial thalli dioecious. Carpogonial branches unknown. Cystocarps (Fig. 158E) sessile on terminal leaflets or becoming stalked, ovoid, 1–2 (–3) mm in diameter, with a thick ostiolate pericarp. Carposporophyte (Fig. 158F) densely tufted, with a basal fusion cell, much branched gonimoblast filaments of slender, elongate, cells and single, terminal, clavate to elongate-ovoid, carposporangia 20–50 (–65) µm in diameter. Spermatangial sori near ends of branches, 1–2 mm across, with spermatangia (Fig. 158G) cut off from initials derived from outer cortical cells, elongate, 2–3 µm in diameter.

Tetrasporangia unknown (a doubtful record in Lucas & Perrin 1947, p. 239).

Type from Georgetown, Tas. (Harvey); lectotype in Herb. Harvey, TCD. (Alg. Aust. Exsicc. 244J).

Selected specimens: Amphitheatre Rock, West I., S. Aust., 13 m deep (Shepherd, 1.i.1969; AD, A33253). 22 km NW of Robe, S. Aust., 40 m deep (Shepherd, 20.xi.1968; AD, A33104). 1.3 km off Cape Northumberland, S. Aust., 15 m deep (Turnbull, 30.ix.1975; AD, A46612). 16 km NW of Cape Bridgewater, Vic., 80–100 m deep (Watson, 16.v.1969; AD, A34761). Cape Woolamai, Vic., 15–18 m deep, S side (Sorokin, 16.ii.1990; AD, A60198). Walkerville, Vic., drift (Sinkora A2316, 7.iii.1976; AD, A48379). Little Squally Cove, Deal I., Bass Strait, 15–28 m deep (Houridis, 12.iii.1993; AD, A63194). Granville Harbour, Tas. (Blackman, 28.i.1979; AD, A58501). Low Head, Tas., drift (Perrin, June 1943; AD, A8469). Bicheno, Tas., 17 m deep (McCauley, 26.ii.1990; AD, A60415). Bluestone Bay, Freycinet Pen., Tas., 6 m deep (Brown et al., 4.xi.1982; AD, A56271). Marion Bay, Tas., 3–5 m deep (Shepherd, 13.ii.1970; AD, A35600). Arch Rock, E of Ninepin Point, Tas., 1–10 m deep (Andrews, 21.x.1994; AD, A64004); 0–5 m deep (Sanderson, 21.x.1994; AD, A63988). Fluted Cape, Bruny I., Tas., 16 m deep (Shepherd, 10.ii.1972; AD, A41522).

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

Distribution: West I., S. Aust., to Walkerville, Vic., and around Tasmania.

Taxonomic notes: P. australasica is a deep-water species on rough-water coasts.


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

CHIHARA, M. & YOSHIZAKI, M. (1978). Anatomical and reproductive features of Ptilonia okadai (Rhodophyta, Bonnemaisoniaceae). Phycologia 17, 382–387.

DE TONI, G.B. (1900b). Sylloge Algarum omnium hucusque Cognitarum. Vol. 4. Florideae. Sect. 2, pp. 387–776. (Padua.)

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

HARVEY, W.H. (1859b). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. HI Flora Tasmaniae. Vol. II, pp. 282–320. (Reeve: London.)

LEVRING, T. (1953). The marine algae of Australia. I. Rhodophyta: Goniotrichales, Bangiales and Nemalionales. Arkiv för Bot. Ser. 2, 2, 457–530.

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

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.

REINBOLD, T. (1898). Die Algen der Lacepede und Guichen Bay (Süd Australien) und deren flatterer Umgebung, gesammelt von Dr. A. Engelhart-Kingston. II. Nuova Notarisia 9, 33–54.

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

TISDALL, H.T. (1898). The algae of Victoria. Rep. 7th Meet. Aust. Ass. Adv. Sci., Sydney, 1898, pp. 493–516.

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

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (28 June, 1996)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIB. Gracilarialse, Rhodymeniales, Corallinales and Bonnemaisoniales
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIB 1996, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.

Illustration in Womersley Part IIIA, 1996: FIG. 158.

Figure 158 image

Figure 158   enlarge

Fig. 158. Ptilonia australasica (A, B, E, AD, A33104; C, AD, A63194; D, F, AD, A60415; G, AD, A63988). A. Habit. B. Transverse sections of young and mid age branches. C. Transverse section of older branch with midrib. D. Longitudinal flat section of branch showing veins and parenchyma. E. Branches with cystocarps. F. Longitudinal section of cystocarp with carposporophyte. G. Section of branch with a spermatangial sorus.

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