Incendia cryptica K.R.Dixon

Scientific Description

Habit and structure. Thallus orange-red to deep red, with faint concentric bands, heavily calcified and brittle, composed of encrusting blades with broad lobes free of the substratum at the margins. Hypothallus composed of sparingly branched and regularly parallel filaments of rectilinear to somewhat distally flared or crispate cells (17–45 µm long and 5–12 µm tall) that give rise to assurgent perithallial filaments above and rhizoids below from their distal ends. Lower perithallus with elongate perithallial coxal cells; lower perithallial cells bearing obliquely or irregularly orientated cellular projections that form secondary pit connections with adjacent cells. Upper perithallus of rectilinear cells 12–28 µm long and 5–10 µm diam. below, decreasing in length distally and having an L:B up to 1 at the dorsal surface. Hairs rarely observed, bullet-shaped, 15–20 µm long and 10–13 µm diam. Rhizoids long, 5–10 µm diam., multicellular, mostly simple, very occasionally branched; basal cell penetrating the thick ventral cuticle.

Reproduction. Reproduction not observed.

Distribution. Known only from Adele Island and White Island in the Kimberley region of north-western Australia.

Habitat. Known from subtidal rock.

[After K.R. Dixon in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 211–215 (2018)]