Lomentaria corallicola Børgesen

Scientific Description

Habit and structure. Thallus with prostrate and erect axes to 8 mm long, pale red. Prostrate axes terete, 100–150 µm diam., attached by rhizoidal holdfasts formed from surface cells near apices, the axes then growing further to form additional prostrate and erect axes. Erect axes mostly simple or sparingly branched, terete or slightly compressed, 100–500 µm diam., broader where reproductive. Structure hollow except at branch bases. Cellular layer 1–3 cells thick, primarily composed of large pale longitudinally elongate or equidimensional cells to 35–60 µm long and 12–25 µm diam., with smaller pigmented cells (5–8 µm diam.) interspersed. Inner surface lined with longitudinal filaments 3–15 µm diam., bearing lateral spherical vesicular cells 6–8 µm diam.

Reproduction. Spermatangia arising in tufts on cortex, mainly on smaller surface cells, these cutting off obpyriform spermatangial mother cells apically and laterally, the latter dividing and forming further series of mother cells. Spermatangia 2–3 µm diam., forming singly or in pairs from mother cells, the fertile structures ultimately forming rosettes around larger cortical cells. Tetrasporangia spherical, 35–50 µm diam., tetrahedrally divided. Other reproductive structures not observed.

Distribution. Widespread in warmer waters of the Indian, Pacific and western Atlantic Oceans.

Habitat. Epilithic or epiphytic.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 328–330 (2018)]