Electronic Flora of South Australia Species Fact Sheet

Dictyosphaeria sericea Harvey 1855c: 565; 1859b: 339, pl. 196A.

Phylum Chlorophyta – Order Siphonocladales – Family Valoniaceae

Selected citations: Lucas 1936: 31, fig. 13. Womersley 1956: 376.

Thallus (Pl. 13, fig. 3) medium green, shallowly cupulate to irregularly lobed, single or grouped, 2–10 cm across and 1 cell thick (Fig. 74H), consisting of a thick, irregular margined membrane from a central (often broad), sessile attachment by coarse rhizoids, epilithic. Cells isodiametric, round to polygonal in surface view, (100–) 150–250 (–300) µm across in upper parts and 300–500 (–1000) gm across near the base of the thallus, 400–600 (–1500) µm thick, with small hapteroid lenticular cells forming rows joining the surface margins of the cells (Fig. 74G–I); new cells formed by segregative division, endogenous, with successive outer walls remaining for some time (Fig. 74H) and later sloughed off; chloroplasts numerous (Fig. 74J), forming a reticulum, the larger ones with a pyrenoid.

Reproduction: Reproduction unknown.

Type from W. Aust. (Clifton); in TCD (see Womersley 1956, p. 376).

Selected specimens: Natural jetty reef, Rottnest I., W. Aust., upper sublittoral (Woelkerling, 10.xi.1968; ADU, A33333). Off Troubridge I., S. Aust., 23 m deep (Shepherd, 4.ii.1969; ADU, A33809). Aldinga, S. Aust., 20 m deep (Mitchell, 12.ii.1961; ADU, A24767). Pennington Bay, Kangaroo I., S. Aust., outer pools on reef (Womersley, 6.i.1947; ADU, A4406). N. side of the Bluff, Victor Harbor, S. Aust., 1 m deep (Clarke, 23.viii.1982; ADU, A53381). Walkerville, Vic., near low tide level on bluff (Sinkora A1498, 21.ii.1972; ADU, A42316). Rocky Cape, Tas., upper sublittoral pools (Wollaston & Mitchell, 24.6.1964; ADU, A27648).

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

Distribution: From Rottnest I., W. Aust. around southern Australia to Walkerville, Vic. and the north coast of Tasmania, from low tide level to 23 m deep on rough-water to moderate coasts.

Taxonomic notes: This is a common species along southern Australia and when in shallow water is often found in shaded areas. Larger cells often show 2–5 inner cells formed by segregative division and the outer walls remain distinct as 2–4 successive layers until the outermost are sloughed off.

References:

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. (1859b). Algae. In J.D. Hooker, the Botany of the Antarctic Voyage. Part III. Flora Tasmaniae. Vol. 2, pp.282–343, Plates 185–196.

LUCAS, A.H.S. (1936). The Seaweeds of South Australia. Pt. I. Introduction and the Green and Brown Seaweeds. (Govt Printer: Adelaide.)

WOMERSLEY, H.B.S. (1956). A critical survey of the marine algae of southern Australia. I. Chlorophyta. Aust. J. mar. freshw. Res. 7, 343–383.

The Marine Benthic Flora of Southern Australia Part I complete list of references.

Author: H.B.S. Womersley

Publication: Womersley, H.B.S. (31 May, 1984)
The Marine Benthic Flora of Southern Australia
Part I
©Board of the Botanic Gardens and State Herbarium, Government of South Australia

Illustrations in Womersley Part I, 1984: PLATE 13 fig. 3; FIG 74 G–J.

Plate 13   enlarge

PLATE 13 Fig. 1. Chaetomorpha coliformis. Robe, S. Aust., from the upper sublittoral, Sept. 1981;
Fig. 2. Chaetomorpha linum. Port MacDonnell, S. Aust., drift (ADU, A53159 collection);
Fig. 3. Dictyosphaeria sericea. Victor Harbor, S. Aust., 1 m deep (ADU, A53381 collection). (Photo by A.C.U.E.)
Fig. 4. Codium galeatum (lower), C. mamillosum (upper left) and C. capitulatum (upper right). Elliston, S. Aust.

Figure 74   enlarge

Fig. 74. A–F. Urospora penicilliformis (ADU, A54021). A. Base of filament with rhizoids. B. Upper filament with recently divided cells. C. Mid filament with elongate cells. D. Mid cells showing chloroplast, pyrenoids and lipid bodies. E. Ditto from upper cells. F. Upper cells with zooids and empty cell with pore. G–J. Dictyosphaeria sericea (ADU, A53381). G. Surface view of thallus, showing recently divided cells and rows of hapteroid lenticular cells. H. Cross section showing old cell walls and lenticular cells prior to sloughing off of older walls. I. Detail of hapteroid lenticular cells. J. Chloroplasts with pyrenoids.

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