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Callipsygma wilsonis J. Agardh. Cribb 1958: 207–208, figs 1–4.

Phylum Chlorophyta – Order Caulerpales – Family Udoteaceae


Gepp & Gepp 1911: 63, figs 144–146. Womersley 1956: 372; 1971a: 116, fig. 11.

Thallus (Fig. 83A) medium green, usually 10–35 cm high, more or less complanately and alternately branched, holdfast to 3 cm across, with lower axes of thallus irregularly subdichotomous to laterally branched and considerably thickened (0.5–1.5 cm in diameter); young branches probably developed seasonally, elongate, bearing subdistichous, alternate, fastigiate (Fig. 84B) to flabellate and complanate branch systems. Flabellate systems (Fig. 84C) 0.5–1.5 cm long, often complanately and di-(tri-) chotomously branched usually 1–2 segments apart, consisting of cylindrical segments with occasional lateral attachment (Fig. 84D) and with perforate end walls (Fig. 84E); upper segments usually (80–) 150–200 µm in diameter and 1–3 (–4) mm long, basal segments to 300 µm in diameter and 300–500 µm long. Axes denuded below but densely covered with chains of short, subspherical to ovoid segments 100–200 µm in diameter (Fig. 84F) which are initiated close the apices and develop to form a very thick layer over the axial row of segments in the lower parts of the thallus.

Reproduction: Reproduction unknown.

Type from Sorrento, Port Phillip Heads, Vic.; in Herb. Agardh, LD, 15723.

Selected specimens: Seal Bay, Kangaroo I., S. Aust., drift (Womersley, 22.xi.1968; ADU, A32954). Robe, S. Aust., drift (Bailey, 18.xi.1967; ADU, A32028). Nora Creina, S. Aust., 1 m deep in shaded pool (Womersley, 16.xii.1970; ADU, A37818-"Marine Algae of southern Australia" No. 16). Point Lonsdale, Vic., shaded low pools (Woelkerling, 6.xi.1977; ADU, A48837). East Cove, Deal I., Bass Strait, 10 m deep (Shepherd & Lewis, 7.v.1974; ADU, A45090). Musselroe Bay, Tas. (Perrin, Feb. 1940; HO, 57914).

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

Distribution: From Vivonne Bay, Kangaroo I., and Port Elliot, S. Aust. to Sorrento, Vic., Deal I. and Cape Barren I., in Bass Strait, and Musselroe Bay, Tasmania. Usually a deep-water species (to 10 m) or in heavily shaded pools.

Taxonomic notes: Callipsygma is a most distinctive alga. While placed in the Udoteaceae, it differs from most other genera (except Rhipiliopsis robusta – see below) in that the thallus is partitioned into regular, multinucleate segments by ingrowing cross walls which almost meet at the centre but usually leave a small perforation. Such regular segments and ingrowing cross walls are similar to the Cladophorales, but Callipsygma is heteroplastic and preliminary microchemical tests indicate that the wall does not contain cellulose.


CRIBB, A.B. (1958). A note on the structure of the green alga—Callipsygma wilsonis J.Ag. Pap. Dep. Bot. Univ. Qld 3(22), 207–208.

GEPP, A. & GEPP, E.S. (1911). The Codiaceae of the Siboga Expedition, including a monograph of Flabellarieae and Udoteae. Monogr. Siboga-Exped. 62, 1–150, Plates 1–22.

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.

WOMERSLEY, H.B.S. (1971a). New records and taxa of marine Chlorophyta in southern Australia. Trans. R. Soc. S. Aust. 95, 113–120.

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: FIGS 83A, 84 B–F.

Figure 83 image

Figure 83   enlarge

Fig. 83. A. Callipsygma wilsonis (ADU, A37818). B. Rhipilia pusilla (ADU, A32893). C. Rhipiliopsis peltata (ADU, A37817). D. Rhipiliopsis robusta (ADU, A41215). E. Avrainvillea clavatiramea (ADU, A33962).

Figure 84 image

Figure 84   enlarge

Fig. 84. A. Pseudocodium australasicum (ADU, A13618). Longitudinal thallus structure. B–F. Callipsygma wilsonis. B. Loosely branched filaments (ADU, A32028). C. Flabellate tuft largely complanately branched. D. Detail of C showing lateral attachments. E. Apex of cell with two daughter cells and perforations between cells; lateral attachment to cell on left; chloroplasts, amyloplasts and acicular crystals. F. Cross section of older part showing short lateral chains of cells. (C–F ADU, A37818)

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