Electronic Flora of South Australia Species Fact Sheet

Dictyopteris australis (Sonder) Askenasy 1888: 30.

Phylum Phaeophyta – Order Dictyotales – Family Dictyotaceae – Tribe Zonarieae

Selected citations: Allender & Kraft 1983: 107, figs 17C,D, 18C,D. Womersley 1949: 113; 1967: 217.'

Synonyms

Haliseris australis Sonder 1853: 664.

Haliseris pardalis Harvey 1855c: 535; 1858, pl. 29.

Thallus (Fig. 76A) medium brown, usually 10–30 cm long, with one to several complanate fronds arising from a matted rhizoidal holdfast 0.2–1.5 cm across and 0.2–1.0 (–1.5) cm long; epilithic. Growth (Fig. 77A) from several apical cells in a rounded apex. Fronds subdichotomously branched at intervals of 3–10 cm, with or without proliferous branchlets from adjacent to the midrib, of fairly uniform width (usually 0.8–1.5 cm) throughout, with a central midrib and usually with faint (microscopic) lateral veins (Fig. 77E), less than 1.5 mm apart, running upwards from midrib to margin; branches often denuded below. Structure (Fig. 77B–D) of wing of cells of similar size, one cell thick (25–40 gm) within 4–10 cells of the margin, becoming two cells thick (60–90 µm) for most of the wing, and 3–4 cells thick near the midrib which is usually 8–10(44) cells thick and has a central core of slenderer cells; cortical cells 16–30 µm across in surface view and L/B (1–) 2–5. Hair tufts (Fig. 77E) dense, arranged in reflexed slight curves from midrib to margin; hairs (Fig. 77C) originating from small lateral derivatives of cortical cells, 14–22 µm in diameter.

Reproduction: Sporangial sori (Fig. 77E) associated with the hair tufts and forming reflexed lines from midrib to margin (Fig. 76A), rarely extending over the blade (ADU, A35699); sporangia (Fig. 77C) external to the cortex, with a laterally elongate stalk cell within the blade, subspherical, 100–160 µm in diameter. Oogonial sori unknown. Antheridial sori (Fig. 77F) scattered, irregularly angular in shape, sunken within the thallus, 400–1500 µm long, 200–1000 µm across; antheridia (Fig. 77G) 25–50 µm long, 20–50 µm in diameter.

Type from Lefevre Pen., S. Aust.; in MEL, 16873.

Selected specimens: Dampier Arch., W. Aust., 1 m deep opposite Haycock I. (Cambridge, 24.viii.1979; ADU, A51773). Cottesloe, W. Aust., 3 m deep (Smith 26, 15.i.1945; ADU, A2096). Tiparra reef, S. Aust., 9 m deep (Shepherd, 9.iv.1986; ADU, A57037). Cape Elizabeth, Yorke Pen., S. Aust., drift 5 km S. (Parsons, 30.iii.1970; ADU, A35698, male, and A35699). Christies Beach, S. Aust., 9 m deep on effluent outlet pipe (Clarke & Engler, 14.ii.1980; ADU, A50865-"Marine Algae of southern Australia" No.193, and 8.5 m deep, 3 m W. of outfall (Clarke & Engler, 26.ii.1980; ADU, A50881). Port Noarlunga, S. Aust., upper sublittoral (Kald, April 1968; ADU, A32543).


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

Distribution: From Dampier Arch., W. Aust., around southern Australia to Port Noarlunga, S. Aust. Queensland, Lord Howe I.

Pakistan, India, Hawaiian Islands.

Taxonomic notes: Dictyopteris australis is readily recognised by the fine lateral veins (though these are occasionally rare, especially in Queensland specimens) and the hair tufts with associated sori of sporangia in reflexed curves from midrib to margin.

References:

ALLENDER, B.M. & KRAFT, G.T. (1983). The marine algae of Lord Howe Island (New South Wales): The Dictyotales and Cutleriales (Phaeophyta). Brunonia 6, 73–130.

ASKENASY, E. (1888). Forschungsreise S.M.S. Gazelle. IV Th. Bot., Algen. pp. 1–58, Plates 1–12.

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.)

SONDER, O.W. (1853). Plantae Muellerianae. Algae. Linnaea 25, 657–709.

WOMERSLEY, H.B.S. (1949). Studies on the marine algae of southern Australia. No. 3. Notes on Dictyopteris Lamouroux. Trans. R. Soc. S. Aust. 73, 113–116, Plate 22.

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 76A, 77 A–G.

Figure 76 image

Figure 76   enlarge

Fig. 76. A. Dictyopteris australis (ADU, A50881). B. Dictyopteris gracilis (ADU, A42542, holotype).

Figure 77 image

Figure 77   enlarge

Fig. 77. A–G. Dictyopteris australis (A,F,G, ADU, A35698; B–D, ADU, A57037; E, ADU, A32543). A. Apex showing central meristem and segmentation. B. Transverse section of margin of thallus. C. Transverse section of thallus with phaeophycean hairs and undivided sporangia. D. Transverse section of midrib and adjacent wing. E. Thallus showing midrib, lateral veins, hair tufts and sporangia. F. Male thallus with antheridial sori. G. Section of male thallus with antheridia. H–M. Dictyopteris gracilis (I–L, ADU, A42542, holotype; H,M, ADU, A38375). H. Apex of thallus with branching midrib and hair tufts. I. Apex showing central meristem and segmentation. J. Apex with tetrasporangia. K. Transverse section of midrib and lateral wing. L. Transverse section of wing and undivided sporangia. M. Transverse section of male thallus with phaeophycean hairs and antheridia.


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