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Electronic Flora of South Australia Species Fact Sheet

Platythalia quercifolia (R. Brown ex Turner) Sonder 1845: 51; 1846: 158.

Phylum Phaeophyta – Order Fucales – Family Cystoseiraceae

Selected citations: Gruber 1896: 24, pl. 7 figs 6,7. Womersley 1967: 256.


Focus quercifolius R. Brown ex Turner 1811: 38, pl. 151.

Clarpoglossum quercifolium (R. Brown) J. Agardh 1848: 193. Harvey 1858, pl. 43.

Thallus (Fig. 148B) dark brown, 15–80 cm long, with one to a few essentially complanately branched axes from the holdfast. Holdfast stoloniferous, 0.5–2 cm across; epilithic. Axes flat, alternately pinnately branched and relatively straight, becoming denuded below, 3–6 mm broad and 0.5–1 mm thick, with marginal laterals (0.5–) 1–2 cm apart. Laterals (Fig. 155A) lying in the same plane as the axis but often basally twisted, simple or basally branched, (2–) 4–10 (–15) cm long and 4–10 mm broad, becoming slightly costate, basally constricted and tapering above, with well developed, subopposite to alternate, coarse marginal spines 2–5 (–10) mm long. Structure of a medulla of elongate cells without rhizoids and a cortex of isodiametric cells with a surface phaeoplastic meristoderm.

Reproduction: Thalli dioecious. Receptacles (Fig. I55A) developed from upper parts or the whole of the laterals. Conceptacles scattered, with surface ostioles, unisexual; oogonia sessile, ovoid, 100–130 µm long and 80–100 µm in diameter, with simple paraphyses ; antheridia on branched paraphyses, ovoid, 30–40 µm long and 10–16 µm in diameter.

Type from "South coast, New Holl." (probably from King George Sound, W. Aust.); in BM.

Selected specimens: Kitson Point, Rottnest I., W. Aust., 1.5 m deep (Engler & Clarke, 6.ix.1979; ADU, A51145). Hamelin Bay, W. Aust., drift ( Womersley, 1.ix.1979; ADU, A50608). Cosy Corner, Torbay Head, W. Aust., drift (Mitchell, 28.ix.1966; ADU, A30788). Point Valliant, Two People Bay, W. Aust., drift (Womersley, 30.viii.1979; ADU, A50950-"Marine Algae of southern Australia" No. 198). Cave Islet, Recherche Arch., W. Aust., in rock pool 20.xi.1950; ADU, A 15869).

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

Distribution: From Geraldton (De Toni & Forti 1923, p. 71) to the Recherche Archipelago, W. Aust.

Taxonomic notes: P. quercifolia is a distinctive alga, with its relatively broad, spinous-margined, laterals.


AGARDH, J.G. (1848). Species, Genera et Ordines Algarum. Vol. 1. (Gleerup: Lund.)

DE TONI, G.B. & FORTI, A. (1923). Alghe di Australia, Tasmania e Nouva Zelanda. Memorie R. Inst. veneto Sci. 29, 1–183.

GRUBER, E. (1896). Ueber Aufbau and Entwickelung einiger Fucaceen. Bibl. Bot. 38, 1–32, Plates 1–7.

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

SONDER, O.W. (1845). Nova Algarum genera et species, quas in itinere ad oras occidentales Novae Hollandiae, collegit L. Preiss. Bot. Ztg 3, 49–57.

SONDER, O.W. (1846). Algae. In Lehmann, C., Plantae Preissianae. Vol. 2, pp. 148–160. (Hamburg.)

TURNER, D. (1811). Fuci sive Plantarum Fucorum Generi a Botanicis Ascriptarum 'cones Descriptiones et Historia. Vol. 3, pp. 1–148, Plates 135–196. (London.)

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

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 148B, 155A.

Figure 148 image

Figure 148   enlarge

Fig. 148. A. Cystophora cuspidata (ADU, A13445). B. Platythalia quercifolia (ADU, A50950).

Figure 155 image

Figure 155   enlarge

Fig. 155. A. Platythalia quercifolia (ADU, A30788). End of a lateral branch with scattered conceptacles. B. Platythalia angustifolia (ADU, A30988). Apex of a branch with laterals containing submarginal conceptacles. C. Myriodesma leptophyllum (ADU, A57326). Upper branches with conceptacles. D. Myriodesma serrulatum (ADU, A51221). Upper branches with raised conceptacles. E. Myriodesma integrifolium (ADU, A57457). Upper branches with conceptacles.

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