Cystophora monilifera J.Agardh

Scientific Description

Habit and structure. Thallus medium brown, openly to moderately densely branched,20–60(–100) cm long, with a robust (especially below) primary axis bearing retroflex secondary axes. Holdfast discoid-conical, 0.5–2 cm across; epilithic. Primary axeswith a short stipe expanding to a flat axis 3–8(–15) mm broad and 1–2 mm thick, with narrow edges, alternately distichously branched from the face at intervals of 0.5–2 cm, with prominent residues of secondary axes on lower and mid primary axes; secondary axes with prominent retroflex bases with broad basal wings, usually denuded above their base with scalariform residues 1–3 mm long, 2–7 mm apart. Laterals slender, 3–8 cm long, tristichously branched with alternately subdistichous, terete, ramuli 0.2–0.5 mm in diameter. Vesicles usually present, replacing 1 or 2 (rarely more) of the basal ramuli of laterals, subspherical, petiolate, mutic, 3–6(–8) mm in diameter.

Reproduction. Thalli monoecious. Receptacles branched, (0.5–)1–2(–3) cm long and 0.5–1 mm in diameter at conceptacles, with scattered conceptacles narrowly to distantly separated by sterile tissue, drying moniliform. Conceptacles bisexual or unisexual, with ostioles scattered or more or less in two rows in plane of branching; oogonia sessile, subspherical to ovoid, 80–120 µm long and 60–110 µm in diameter; antheridia sessile or on branched paraphyses, elongate-ovoid, 20–30 µm long and 7–12 µm in diameter.

Distribution. From Nickol Bay, W. Aust., around southern Australia and the north coast of Tas., to Long Bay, N.S.W.

Habitat. C. monilifera is a widespread species, from (0.5–)2–42 m deep on coasts of considerable to moderate water movement.

[After Womersley, Mar. Benthic Fl. Southern Australia II: 382 (1987)]