Ulva lactuca L.

Sp.Pl. 1163 (1753)
Conservation Code
Not threatened
Naturalised Status
Native to Western Australia
Name Status

Scientific Description

Habit and structure. Thallus grass-green, usually with a single frond from the holdfast, entire or irregularly lobed or divided, to 15 cm long and 1–10 cm across; margin entire, surface smooth. Cells in surface view in short rows becoming more irregular below, isodiametric to slightly elongate, (10–)12–18(–20) µm across or long above, 20–25 µm long below; pyrenoids 1–2(–3) per cell. Thallus 40–60 µm thick in upper parts with cells in sectional view rather square to rectangular, L/B 1.0–1.4 and 18–22 µm long; 60–85 µm thick in mid and lower parts with cells in section L/B 1–1.2(–1.4) and 22–26 µm long, becoming 75–100(–250) µm thick near the base with a narrow to moderately broad central mass of rhizoids.

Reproduction. Generations isomorphic, the sporophyte producing quadriflagellate zoo(meio)spores, and the gametophytes unisexual with biflagellate anisogametes which can germinate directly to form the gametophyte again.

Distribution. Recorded from several locations in W. Aust. In southern Australia, known from Christies Beach and St Kilda, S. Aust. and Port Phillip, Vic.

[After Womersley, Mar. Benthic Fl. Southern Australia I: 141 (1984)]

John Huisman & Cheryl Parker, 3 August 2021


IBRA Regions
Carnarvon, Jarrah Forest, Swan Coastal Plain.
IBRA Subregions
Cape Range, Perth, Southern Jarrah Forest.
IMCRA Regions
Abrolhos Islands, Central West Coast, Leeuwin-Naturaliste, Pilbara (offshore), Shark Bay, WA South Coast.
Local Government Areas (LGAs)
Albany, Ashburton, Cockburn, Cottesloe, Fremantle, Greater Geraldton, Irwin, Joondalup, Karratha, Mosman Park, Nedlands, Peppermint Grove, Perth, Port Hedland, Rockingham, Shark Bay, South Perth, Subiaco, Wanneroo.