Exophyllum wentii Weber Bosse

Scientific Description

Habit and structure. Thallus light to deep red, mottled, decumbent, spreading to 14 cm, flattened, tough and cartilaginous, forming a broad blade or with numerous marginal cylindrical outgrowths, these attaching to the substratum and forming additional stellate or irregularly shaped blades. New growth generally stalked, with a thin substellate blade with several apices, the blades thickening rapidly and becoming irregularly shaped. Medulla of spherical to longitudinally elongate cells, those of the central medulla 150–250 µm long, 50–100 µm wide, grading outwardly to smaller and more spherical cells. All cells with numerous secondary pit connections. Cortex grading from the outer medulla, with 2 or 3 layers of pigmented cells, the outermost ellipsoidal to cuboidal, 5–8 µm diam.

Reproduction. Tetrasporangia in stalked surface stichidia, in linear paired series with up to 6 pairs. Other reproductive structures not observed.

Distribution. In north-western Australia known only from the Montebello Islands and the Dampier Peninsula; otherwise recorded from Indonesia, the Philippines and Japan.

Habitat. Recorded in the lower intertidal and shallow subtidal.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 509–510 (2018)]