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Petalonia fascia (Müller) Kuntze. Hamel 1937: 197.

Phylum Phaeophyta – Order Scytosiphonales – Family Scytosiphonaceae

Selected citations: Lindauer et al. 1961: 255, fig. 64 (5–7). Nakamura & Tatewaki 1975: 72, figs 11–14 p1. 3. Rosenvinge & Lund 1947: 31, fig. 10. Taylor 1957: 167, pl. 14 fig. 5, pl. 15 fig. 3. Womersley 1967: 245. Wynne 1969: 17, figs 6–8, pls 6–13d.

Thallus (Fig. 106A) medium to dark brown, flat, simple or split above, broadly lanceolate to ligulate with a cuneate base, 5–30 cm high and (0.5–) 1–6 cm broad, with one to several fronds from a small discoid holdfast 0.5–1 (–2) mm across; epiphytic or epilithic. Structure polystichous, 100–300 µm thick, with a medulla 2–4 (–8) cells thick, of large and small, clear, irregularly placed cells (Fig. 109B) and a cortex 1–2 cells thick, outer cells more or less in longitudinal rows (Fig. 108A), isodiametric, 6–8(40) across in surface view; phaeophycean hairs rare to frequent, single or in small groups, scattered, becoming sunken in a pit, 4–6 µm in diameter; cortical cells with a single phaeoplast and pyrenoid, with scattered or grouped cells in some specimens with uniform, yellowish, darkly-staining contents (Fig. 108A,B).

Reproduction: Sori (Fig. 108A,B) extending over most of the surface, often in longitudinal patches, without paraphyses (but including the yellowish cortical cells when present); plurilocular organs 20–30 µm and 4–6 locules high, 6–8 µm in diameter, consisting of 4 (–8) vertical rows from each cortical cell.

Type from Christiansund, Norway; probably non-existent.

Selected specimens: Cottesloe, W. Aust., Grant Str. reef (Smith, 15.vii.1944; ADU, A4543). Outer Harbour, Port Adelaide, S. Aust., lower eulittoral on breakwater (Womersley, 16.vii.1950; ADU, A13280). Port Stanvac, S. Aust., lower eulittoral on jetty piles (Lewis, 16.viii.1972; ADU, A42638). Robe, S. Aust., tow eulittoral inside point (Womersley, 9.ix.1968; ADU, A32693-"Marine Algae of southern Australia" No.50) and on Amphibolis antarctica, 1–2 m deep near jetty (Womersley, 12.ix.1983; ADU, A54300). Port MacDonnell, S. Aust., lower eulittoral on rope (Womersley, 16.x.1985; ADU, A57003). Gunnamatta Beach, Mornington Pen., Vic. (Sinkora A863, 20.ix.1970; ADU, A53454). Bridport, Tas. (Aug. 1953; HO, 67183). Taroona, Tas., drift (Curtis, 1.xi.1963; HO, 67182). Cronulla, N.S.W. by CSIRO boatsheds (Womersley, 22.viii.1945; ADU, A2073). Manly, N.S.W. (Lucas, Nov. 1931; SYDNEY).

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

Distribution: Widely distributed in temperate waters.

In southern Australia, from Cottesloe, W. Aust. to Manly, N.S.W., and around Tasmania. The erect stage is found throughout the winter (May to October), epilithic or on Amphibolis and Posidonia.

Taxonomic notes: The crustose stage has not been positively identified in southern Australia, but may be represented by epiphytic discs on old parts of Posidonia australis leaves at Nora Creina, S. Aust.; upper sublittoral ( Womersley, 26.ii.1984; ADU, A54827).

Most specimens have both the cortex and sori without paraphysis-like cells, but in two (ADU, A54300 and A2073), larger cortical cells occur with uniform, yellow-brown contents similar to the paraphyses of Scytosiphon but shorter and not confined to the sori.


HAMEL, G. (1937). Phéophycées de France. Fasc. III, pp. 177–240. (Paris.)

LINDAUER, V.W., CHAPMAN, V.J. & AIKEN, M. (1961). The marine algae of New Zealand. II. Phaeophyceae. Nova Hedwigia 3, 129–350, Plates 57–97.

NAKAMURA, Y. & TATEWAKI, M. (1975). The life history of some species of the Scytosiphonales. Sci. Pap. Inst. Algol. Res. Hokkaido Univ. 6, 57–93, Plates 1–5.

ROSENVINGE, L.K. & LUND, S. (1947). The marine algae of Denmark. Vol. II. Phaeophyceae. III. Encoeliaceae, Myriotrichiaceae, Giraudiaceae, Striariaceae, Dictyosiphonaceae, Chordaceae and Laminariaceae. K. Dan. Vidensk. Selsk. Biol. Skr. 4(5), 1–99.

TAYLOR, W.R. (1957). Marine algae of the Northeastern coast of North America. Rev. Edn. (Univ. Mich. Press: Ann Arbor.)

WOMERSLEY, H.B.S. (1967). A critical survey of the marine algae of southern Australia. II. Phaeophyta. Aust. J. Bot. 15, 189–270.

WYNNE, M.J. (1969). Life history and systematic studies of some Pacific North American Phaeophyceae (brown algae). Univ. Calif Publ. Bot. 50, 1–88.

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

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
Part II
©Board of the Botanic Gardens and State Herbarium, Government of South Australia

Illustrations in Womersley Part II, 1997: FIGS 106A, 108A,B.

Figure 106 image

Figure 106   enlarge

Fig. 106. A. Petalonia fascia (ADU, A54300). B. Scytosiphon lomentaria, constricted form (ADU, A24419). C. Scytosiphon lomentaria, compressed form (ADU, A19055).

Figure 108 image

Figure 108   enlarge

Fig. 108. A,B. Petalonia fascia (ADU, A54300). A. Surface view of thallus with a sorus of plurilocular organs and paraphyses (stippled). B. Transverse section of thallus with plurilocular organs and paraphyses (stippled). C,D. Scytosiphon lomentaria ( C, ADU, A24419; D, ADU, A52004, sporophyte). C. Transverse section of thallus with cortex, plurilocular organs, paraphyses and phaeophycean hairs. D. Transverse section of sporophytic crust with plurilocular sporangia; one erect filament shown with phaeoplasts. E,F. Colpomenia sinuosa (ADU, A51846). E. Surface pattern of punctate sori around hair tufts. F. Transverse section with part of sorus with phaeophycean hair tufts, plurilocular organs, large paraphyses and cuticular membrane. G.H. Colpomenia peregrina (ADU, A55731). G. Surface pattern of spreading sorus and hair tufts. H. Transverse section with part of sorus, with plurilocular organs, paraphyses and phaeophycean hairs. I–K. Colpomenia ecuticulata (ADU, A53175). I. Surface pattern of reticulate sorus and hair tufts. J. Surface view of cells, plurilocular organs and paraphyses. K. Transverse section with phaeophycean hair tuft and part of sorus with plurilocular organs and 2-celled paraphyses.

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