Cladophora vagabunda (L.) C.Hoek

Scientific Description

Habit and structure. Thallus light to medium green, forming densely branched tufts 2–6 cm high of fasciculate branch systems or more elongate strands 4–30 cm high, with numerous pseudodichotomous axes attached by rhizoids from the basal region, usually occurring under calm to moderate water movement, epilithic or sometimes epiphytic, also forming diffuse loose masses or attached plants in lagoons and saltmarsh ponds; filaments branched from almost every cell above with slightly falcate or straight and usually unilateral fascicles, with the filaments increasing markedly in diameter shortly below the apical cells or just below the fascicles; in lagoon plants these fascicles are less distinct. Growth acropetal and mainly apical above, with intercalary divisions in the mid and lower thallus cells thus separating the laterals by 2–8 or more cells, with occasional intercalated laterals arising below new cross walls; especially in lagoon plants this intercalary growth may be conspicuous; parent cells bearing 1–3(–6) laterals at acute to (usually) broad angles; basal cross walls of laterals oblique to parent cells, becoming later almost horizontal. Apical cells (25–)30–50(–70) µm in diameter, L/B 2–16, cylindrical or often tapering, with rounded apices; ultimate branch cells 25–90 µm in diameter, L/B 2–17; lower thallus cells 85–215 µm in maximum diameter (mostly about 150 µm), L/B 1.5–10; ratio of mid and lower cell to apical cell diameters 2–4(–6); pale plants from lagoons and saltmarsh ponds tend to be slenderer and longer celled; cell walls 1–3 µm thick above, becoming 10–15 µm thick and lamellate below.

Reproduction. By apical and subapical cells forming zooidangia; elsewhere, by biflagellate gametes and quadriflagellate zoospores.

Distribution. Cosmopolitan in tropical and temperate waters. From north of Perth (e.g. from N.W. Cape), W. Aust., around southern Australia and Tas., to Bowen, Qld. Probably a widely distributed species on most coasts of Australia.

Habitat. On sublittoral and lower eulittoral rocks, in rock pools, in lagoons and saltmarsh ponds.

[After van den Hoek & Womersley in Womersley, Mar. Benthic Fl. Southern Australia I: 202–203 (1984)]