Gloioderma iyoense Okamura

Scientific Description

Habit and structure. Thallus soft and mucilaginous, pale red, with prostrate and erect branches, spreading to 14 mm in extent, attached to the substratum at several points. Primary axes terete to compressed, to 1 mm wide, percurrent, pinnately to radially branched, the latter particularly near the rounded apices. Medullary filaments in longitudinal files, with cells 60–145 long and 25–100 diam., with numerous secondary pit connections. Cortical files anticlinal, 50–75 long, 1–3 times dichotomously branched; terminal branch 2 or 3 cells long, composed of pigmented ellipsoidal cells 7–12 long and 2–4 diam.

Reproduction. Spermatangia in sori on primary axes and at the bases of lateral branches, forming candelabra-like clusters on outer cortical cells, spherical and c. 2.5 diam. Cystocarps on the surface of primary axes or terminal on short lateral branches, 580–650 diam., generally with 5–7 pericarpial horns, these occasionally absent. Tela arachnoidea present. Carposporangia 25–30 diam. Tetrasporangia scattered in an unmodified or slightly raised cortex, arising laterally from basal cells of cortical files, ovoid to ellipsoidal when immature, becoming subspherical to ellipsoidal, 35–40 long, 30–35 diam., cruciately or decussately divided.

Distribution. Widespread in warmer seas; in Western Australia south to the Houtman Abrolhos Islands.

Habitat. Epilithic or epizoic in the subtidal.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 317–318 (2018)]