Electronic Flora of South Australia Species Fact Sheet

Myriodesma quercifolium (Bory) J. Agardh 1848: 192; 1894b: 93.

Phylum Phaeophyta – Order Fucales – Family Cystoseiraceae

Selected citations: Nizamuddin & Womersley 1967: 379, pls 72B, 73 fig. 8.

Synonyms

Lessonia quercifolia Bory 1826d: 322; 1828: 79, pl. 4.

Myriodesma latifolium Harvey 1855c: 534; 1858, pl. 24. J. Agardh I894b: 92.

Thallus (Fig. 154A) medium to dark brown, 20–50 cm long, with few to several cornplanately branched fronds from the branched stipe. Holdfast discoid-conical, 3–8 mm across; epilithic. Stipe 8–15 (–25) cm long, with 2–5 di- or trichotomies at intervals of 1–4 (–8) cm, each 2–5 mm in diameter. Fronds 15–30 cm long, irregularly alternately pinnate with laterals 2–6 cm apart, (0.7–) 1–2.5 (–4) cm broad, usually with coarsely serrate margins especially above, rarely with few or no serrations; serrations with rounded ends; midrib conspicuous below, disappearing above. Structure of fronds 250–500 µm and mostly 8–10 cells thick, with a medulla of elongate cells and a cortex of isodiametric cells with an inactive phaeoplastic meristoderm.

Reproduction: Thalli monoecious. Conceptacles (Fig. 156D,E) densely scattered over the fronds, bisexual, with a basal group of phaeophycean hairs becoming paraphyses; oogonia sessile, ovoid, 80–140 µm long and 40–65 µm in diameter; antheridia mostly sessile, or on short branched paraphyses, elongate-ovoid, 20–30 µm long and 6–10 µm in diameter.

Type from "du Sud de Nouv. Holl." (Lesueur); in Herb. Bornet, PC.

Selected specimens: Geraldton, W. Aust. (Lucas, July 1928; in Herb. Lucas, NSW). Port Denison, W. Aust., drift ( Womersley, 31.viii.1947; ADU, A5868). Mandurah, W. Aust., drift (Wollaston, 4.ii.1957; ADU, A22246). Flinders Bay, W. Aust., drift (Womersley, 1.ix.1979; ADU, A50637). Hopetoun, W. Aust., drift (Gordon, 20.xi.1968; ADU, A34130). 16 km E. of Eucla, S. Aust., drift ( Womersley, 3.ii.1954; ADU, A19256). Elliston, S. Aust., drift ( Womersley, 13.i.1951; ADU, A13435). Pearson I., S. Aust., 48 m deep (Shepherd, 9.i.1969; ADU, A33718-"Marine Algae of southern Australia", No. 57). Investigator Str., S. Aust., 34 m deep, 35°27'S, 137°17'E (Watson, 20.i.1971; ADU, A39202). Seal Beach, Kangaroo I., S. Aust., drift ( Womersley, 24.i.1957; ADU, A20743). Port Elliot, S. Aust. (AIg. Muell., MEL, 18852).

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

Distribution: From Geraldton, W. Aust. to Port Elliot, S. Aust.

Taxonomic notes: M. quercifolium is a deep water western species, characterised by the long, broad, prominently serrate laterals. Some W.Aust. specimens (e.g. ADU, A22246) are relatively narrow (8–10 mm broad in mid parts) but otherwise agree with M. quercifolia.

As stated under M. calophyllum, there is some doubt as to whether the latter species is distinct from M. quercifolium, since some western specimens of the latter have few marginal spines.

References:

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

AGARDH, J.G. (1894b). Analecta Algologica. Cont. II. Ada Univ. lund. 30, 1–98, Plate 1.

BORY DE ST-VINCENT, J.B. (1826d). Lessonie. Dict. Class. d'Hist. Nat. 9, 321–322.

BORY DE ST-VINCENT, J.B. (1828). In Duperrey, L.I., Voyage autour du monde, exécuté par ordre du Roi, sur la corvette de Sa Majesté, la Coquille, pendant les années 1822, 1823, 1824 et 1825. Botanique, Cryptogamie, pp. 1–300, Plates 1–39. (Paris.)

HARVEY, W.H. (1855c). Some account of the marine botany of the colony of Western Australia. Trans. R. Ir. Acad. 22, 525–566.

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

NIZAMUDDIN, M. & WOMERSLEY, H.B.S. (1967) The morphology and taxonomy of Myriodesma (Fucales). Nova Hedwigia 12, 373–383, Plates 69–73.

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 154A, 156D,E.

Figure 154   enlarge

Fig. 154. A. Myriodesma quercifolium (ADU, A33718). B. Myriodesma calophyllum (ADU, A46823).

Figure 156   enlarge

Fig. 156. A,B. Myriodesma harveyanum (A, ADU, A57375; B, ADU, A3311). A. Upper branches with conceptacles. B. Transverse section of thallus with bisexual conceptacles each with a central columella bearing phaeophycean hairs. C. Myriodesma tuberosum (ADU, A51679). Upper branches with conceptacles. D,E. Myriodesma quercifolium (D, ADU, A33718; E, ADU, A13435). D. Mid and apical parts of a branch. E. Transverse section of thallus with a bisexual conceptacle and central group of phaeophycean hairs. F. Myriodesma calophyllum. Mid and apical parts of a branch with conceptacles.

Email Contact: State Herbarium of South Australia