Cystophora botryocystis Sond.

Scientific Description

Habit and structure. Thallus medium to dark brown, 0.5–2(–4) m long, with long, basally denuded axes and densely tufted laterals. Holdfast discoid-conical, 5–15 mm across, with a single primary axis; epilithic or occasionally epiphytic on Amphibolis. Primary axes slightly compressed and quadrangular with rounded edges in transverse section, 1.5–5 mm broad and 1–2.5 mm thick, often flexuous, with alternately distichous laterals or secondary axes from the faces of the axes; secondary axes often long but irregular in occurrence; lower parts of axes usually denuded, with short stubby residues. Laterals 5–15(–20) cm long, (0.5–)1–4 cm apart on the axes, densely covered on all sides with short (0.5–1.5 cm long), terete, mostly simple ramuli, with clustered vesicles at their base. Vesicles spherical to slightly ovoid, 3–6 mm long and 3–4 mm in diameter, mutic.

Reproduction. Thalli monoecious. Receptacles simple, terete and smooth to very slightly torulose when fresh, slightly compressed or three-sided when dried, 0.5–1.5(–2) cm long and 1–1.5 mm broad. Conceptacles bisexual or often unisexual, scattered but with ostioles more or less in 2 or 3 rows; oogonia sessile, ovoid, 80–120 µm long and 60–80 µm in diameter; antheridia on branched paraphyses, ovoid, 20–25 µm long and 8–10 µm in diameter.

Distribution.From Cottesloe, W. Aust., and Cape Donington (E. of Port Lincoln), through the Gulf Region of S. Aust. to Port Phillip, Vic., and the N coast of Tas.

Habitat. C. botryocystis is a deep water species on coasts of moderate to slight wave action.

[After Womersley, Mar. Benthic Fl. Southern Australia II: 378–380 (1987)]