Callipsygma wilsonis J.Agardh

Scientific Description

Habit and structure. Thallus 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, fastigiated to flabellate and complanate branch systems. Flabellate systems 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 and with perforate end walls; 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 which are initiated close to the apices and develop to form a very thick layer over the axial row of segments in the lower parts of the thallus.

Reproduction. Unknown.

Distribution. From Rottnest I., W. Aust., Vivonne Bay, Kangaroo I., and Port Elliot, S. Aust., to Sorrento, Vic., Deal I., and Cape Barren I., in Bass Strait, and Musselroe Bay, Tas.

Habitat. Usually a deep-water species (to 10 m) or in heavily shaded pools.

[After Womersley, Mar. Benthic Fl. Southern Australia I: 247 (1984)]