Ulva ralfsii (Harv.) Le Jol.

Scientific Description

Habit and structure. Thallus often unattached, tangled among other algae or forming dense beds of wispy tubular filaments, these mostly unbranched and of similar diameter throughout, or branched near the base, the laterals very elongate and of a uniform diameter throughout their length. Primary axes to 130 μm wide, with up to 6 longitudinal cell rows visible in surface view; laterals to 45 μm wide with 2 or 3 cell rows, tapering to uniseriate apices 10–12 μm wide. Cells of primary and lateral axes square to rectangular in surface view, 34–60 µm long, 24–45 μm wide; cytoplasm concentrated centrally and with 3–7 pyrenoids per cell.

Distribution. Widespread. Although few collections are known, this species can be very common locally.

Habitat. Epiphytic or entangled in other algae.

[After Huisman, Algae of Australia: Mar. Benthic Algae of North-western Australia, 1. Green and Brown Algae 30 (2015)]