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Electronic Flora of South Australia Species Fact Sheet

Dictyopteris muelleri (Sonder) Reinbold 1899: 43.

Phylum Phaeophyta – Order Dictyotales – Family Dictyotaceae – Tribe Zonarieae

Selected citations: Womersley 1967: 218.


Haliseris muelleri Sonder 1853: 665. Harvey 1860: pl. 180.

Thallus (P1. 1 fig. 2; Fig. 78B) medium to dark brown, usually 20–40 cm long, with one to several complanate fronds arising from a matted rhizoidal holdfast 0.2–2.0 cm across and 0.2–1.0 cm long, epilithic. Growth from a row of 4–8 apical cells in a slightly depressed apex, with an entire margin below the apex. Fronds subdichotomously to alternately branched at intervals of 2–10 cm, without proliferations except following damage, blades linear or increasing in width above, often slightly narrowed at branchings, (0.5–) 1–2 (–3.5) cm broad, apices broadly rounded, with a central midrib which is slight above and prominent below with stupose hairs, without lateral veins, wing often denuded below. Structure (Fig. 79E,F) of wing 4–7 cells thick at margin, 4–5 cells thick generally, and the midrib 8–15 (–20) cells thick; cortical cells 25–50 µm across in surface view, L/B 1–2. Hair tufts dense, scattered, hairs arising from a compact group of cells, becoming sunk within the cortex, readily lost, 16–22 µm in diameter.

Reproduction: Sporangia (Fig. 79G,H) densely scattered between midrib and margin (rarely on the midrib) with a very narrow sterile marginal zone, derived from cortical cells and remaining sunken within the cortex, with a laterally elongate stalk cell; sporangia subspherical to ovoid, 80–120 µm in diameter, irregularly tetrahedrally divided. Oogonial sori unknown. Antheridial sori (Fig. 791) small, scattered, angular and irregular in shape, derived from cortical cells and lying within the thallus, (100–) 200–500 µm across; antheridia (Fig. 79J) 40–60 µm long and 20–30 µm in diameter.

Type from Lefevre Pen., S. Aust; lectotype in MEL, 16837.

Selected specimens: Geelvink Channel (50 km N. of Geraldton), W. Aust., 37 m deep (France, Feb. 1979; ADU, A51709). Cottesloe, W. Aust., drift (Smith, April 1943; ADU, A2031). Elliston, S. Aust., drift (Womersley, 27.ii.1959; ADU, A22273). Pennington Bay, Kangaroo I., S. Aust., drift ( Womersley, 22.i.1948; ADU, A6444). Investigator Str., S. Aust., 11 m deep (Watson Stn Y1, 35°12'S, 137°17'E, 20.i.1971; ADU, A38376). Glenelg, S. Aust., drift ( Womersley, 26.iv.1986; ADU, A57063, sporangial and male). Somerton Beach, S. Aust., drift (Womersley, 29.v.1949; ADU, A10830). Port MacDonnell, S. Aust., upper sublittoral pools ( Womersley, 25.i.1967; ADU, A31658). Walkerville, Vic., at low tide (Sinkora A2050, 24.ii.1975; ADU, A48323). Taroona, Tas., 0–10 m deep (Shepherd, 4.ii.1970; ADU, A35568).

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

Distribution: From Geelvink Channel, W. Aust. around southern Australia and Tasmania to Port Jackson, N.S.W. (May 1939, p. 200).

Taxonomic notes: D. muelleri is the commonest species of Dictyopteris on southern Australian coasts, being frequent in pools on rough-water coasts as well as to depths of 37 m. Deeper specimens tend to be broader with thinner and lighter brown fronds. On dying, the fronds lose fucoxanthin readily and become green-brown.


HARVEY, W.H. (1860). Phycologia Australica. Vol. 3, Plates 121–180. (Reeve: London.)

MAY, V. (1939). A key to the marine algae of New South Wales. Part. II. Melanophyceae (Phaeophyceae). Proc. Linn. Soc. N.S.W. 64, 191–215.

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

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: PLATE 1 fig. 2; FIGS 78B, 79 E–J.

Plate 1 image

Plate 1   enlarge

PLATE 1 fig. 1. Ralfsia verrucosa at Port Noarlunga, S. Aust. (ADU, A57427).
fig. 2. Dictyopteris muelleri. An upper sublittoral plant photographed on rock, Robe, S. Aust.

Figure 78 image

Figure 78   enlarge

Fig. 78. A. Dictyopteris acrostichoides (ADU, A55432). B. Dictyopteris muelleri (ADU, A31658). C. Dictyopteris nigricans (ADU, A2296, holotype).

Figure 79 image

Figure 79   enlarge

Fig. 79. A–D. Dictyopteris acrostichoides (ADU, A55432). A. Transverse section of edge of wing. B. Transverse section of mid wing. C. Tetrasporangial thallus showing broad sterile zone between sporangia and margin. D. Transverse section with undivided tetrasporangia. E–J. Dictyopteris muelleri (ADU, A57063). E. Transverse section of edge of wing. F. Transverse section of part of midrib and lateral wing with rhizoids on both sides of midrib. G. Tetrasporangial thallus with midrib and hair tufts. H. Transverse section of thallus with tetrasporangia and a phaeophycean hair tuft. I. Male thallus with antheridial sori and hair tufts. J. Transverse section of thallus with antheridia. K,L. Dictyopteris nigricans (ADU, A4345). K. Transverse section of wing from edge to a phaeophycean hair tuft. L. Transverse section with an undivided sporangium.

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