Electronic Flora of South Australia Species Fact Sheet
Phylum Phaeophyta – Order Ectocarpales
Ectocarpus sordidus Harvey 1859b: 294. Womersley 1967: 191.
Thallus (Fig. 10B) medium brown, forming loose tangled masses 5–30 (–100) cm across, on larger algae or seagrasses or free floating, with sparse branching (Fig. 11F) usually many cells apart; short laterals, irregularly arranged, are usually present near ends of longer branches, and rhizoid-like lateral branches (Fig. 11G), occasionally clustered and of a few cells, are usually present on large branches. Filaments (Fig. 11G) with long, only occasionally branched, axes (25–) 30–50 (–60) µm in diameter with cells L/B 1–1.5 (–2), then tapering to branchlets 10–20 Aim in diameter with cells L/B 1–1.5 (–2.5), with a conical apical cell when young and when mature terminating in a false hair (6–) 8–10 (–15) µm in diameter with cells L/B 4–8. Growth from scattered and often indistinct meristematic regions in axes and main branches (Fig. 11F) with more defined meristems at the base of branchlets. Cells with numerous discoid to lobed or elongate (L/B 2–4) and often irregularly shaped phaeoplasts each with one (–2) pyrenoid, and only few or inconspicuous physodes.
Reproduction: Plurilocular sporangia (Fig. 11G,H) scattered or occasionally grouped, sessile (or rarely pedicellate), conical, reflexed forward, (40–) 50–70 µm long and 20–40 µm in diameter, L/B 2–3. Unilocular sporangia (Fig. 11I) on separate plants, scattered, sessile, ovoid, 35–50 µm long and 20–35 µm in diameter.
Type from George Town, Tas.; holotype in TCD, isotype in BM.
Selected specimens: Coffin Bay, S. Aust., upper sublittoral on flats (Womersley, 10.i.1951; ADU, A13755). Rabbit I., Pelican Lagoon, American R. inlet, Kangaroo I., S. Aust., 1–2 m deep ( Womersley, 31.v.1947; ADU, A5805). Vivonne Bay, Kangaroo I., S. Aust., in shaded end of large rock pool, S. side of Ellen Point (Womersley, 14.i.1948; ADU, A8210 and 30.i.1956; ADU, A20288-unilocular). Port MacDonnell, S. Aust., drift (Womersley, 21.iv.1984; ADU, A55332-"Marine Algae of southern Australia" No. 243). Crawfish Rock, Westernport Bay, Vic., 4 m deep (Watson, 29.v.1974; ADU, A45397).
Distribution: In southern Australia, from Coffin Bay, S. Aust., to Crawfish Rock, Westernport Bay, Vic. and the north coast (at least) of Tasmania.
Clayton (1974, p. 786) records G. sordida from Hayman I., Qld, but it is unknown outside Australia (see Clayton 1974, p. 786).
This species is confined to calm, sheltered bays and inlets, or to sheltered rock pools.
Taxonomic notes: G. sordida differs from other species of Giffordia in its loose, tangled habit, in its sparse branching, and in production of plurilocular and unilocular sporangia on separate plants, implying gametophytic and sporophytic generations (Clayton 1974, p. 790).
CLAYTON, M.N. (1974). Studies on the development, life history and taxonomy of the Ectocarpales (Phaeophyta) in southern Australia. Aust. J. Bot. 22, 743–813.
HARVEY, W.H. (1859b). Algae. In Hooker, J.D., The Botany of the Antarctic Voyage. Part III. Flora Tasmaniae. Vol. 2, pp. 282–343, Plates 185–196.
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.
Womersley, H.B.S. (14 December, 1987)
The Marine Benthic Flora of Southern Australia
©Board of the Botanic Gardens and State Herbarium, Government of South Australia
Illustrations in Womersley Part II, 1997: FIGS 10B, 11 F-I.
Figure 10 enlarge
Fig. 10. A. Acinetospora crinita (ADU, A54824). B. Giffordia sordida (ADU, A55332). C. Giffordia sandriana on Posidonia (ADU, A42716). D. Giffordia mitchelliae on Cystophora intermedia (ADU, A46789). E. Giffordia granulosa (ADU, A39491).
Figure 11 enlarge
Fig. 11. A–E. Acinetospora crinita (ADU, A22658). A. Branching pattern. B. Branches with meristematic regions. C. Plurilocular sporangium with large loculi and two monosporangia. D. Plurilocular organ ("antheridium"). E. Unilocular sporangium. F–I. Giffordia sordida (F–H, ADU, A45397; I, ADU, A10288). F. Branching pattern (meristematic regions shown by flexuous lines). G. Filament with sparse laterals and pluriLocular sporangia; short rhizoidal branch on basal filament. H. Plurilocular sporangia. I. Filaments with rhizoidal laterals and unilocular sporangia.
State Herbarium of South Australia