Gayliella choi Huisman

Scientific Description

Habit and structure. Thallus red, with prostrate and erect axes to 1.7 mm long; prostrate axes attached by unicellular rhizoids arising from periaxial cells; erect axes complanate, with straight apices, alternately branched every 5 or 6 cells in primary axes, (7–) 8 or 9 cells in lateral axes. Axial cells of prostrate axes 30–40 µm diam. [L:B 2–7]; axial cells of erect axes 25–30 µm diam. [L:B 1–7], shorter and rhomboidal near apices. Nodes 35–50 µm diam. [L:B 0.6–1], with 3 periaxial cells (often 4 at dichotomies), each with 2 or 3 acropetal cells and 1 transversely elongate basipetal cell, these remaining undivided or dividing once. Mature basipetal cells rarely with a lateral or oblique division. Acropetal cells often with a hair.

Reproduction. Tetrasporangia 1 or 2 per node, initially adaxial, when single in linear or offset series, often paired and opposite in nodes with 4 periaxials at dichotomies, involucrate (covering 60–90% of the tetrasporangium), spherical, 40–45 µm diam., tetrahedrally divided. Other reproductive structures not observed.

Distribution. Known from the Dampier Archipelago and the Montebello Islands, north-western Australia.

Habitat. Epiphytic in the subtidal.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 413–415 (2018)]