Ethelia denizotii K.R.Dixon

Scientific Description

Habit and structure. Thallus crustose, brownish orange, thin, closely appressed to the substratum over the entire ventral surface, lacking peg-like haptera, 50–225 μm thick, composed of horizontally spreading irregularly branched primary axial filaments giving rise to paler lesser axial filaments of similar dimension, these developing a thin ventral cortex and a comparatively thick dorsal cortical layer. Axial filaments composed of darkly staining cells 25–45 μm long and 17–25 μm diam. Dorsal cortex composed of assurgent filaments, the inner cells 15–45 μm long and 7–20 μm diam., decreasing in size distally, the terminal cells variously cuboidal. Ventral cortex incomplete, typically 1 or 2 cells thick, composed of small-celled rhizoidal filaments; 1- or 2-celled darkly staining structures (possibly immature tetrasporangia) embedded in the outer cortex in otherwise unspecialised sori.

Distribution. North-western Australia.

Habitat. Epilithic in the subtidal.

[After K.R. Dixon in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 182 (2018)]