Titanophora pikeana (Dickie) Feldmann

Scientific Description

Habit and structure. Thallus erect, but sometimes forming secondary attachments, to 15 cm tall, pale pink to whitish, mucilaginous, lightly calcified, arising from a discoid holdfast, flattened, foliose to irregularly dichotomously branched with numerous marginal branchlets. Branches 10–15 mm wide near the base, tapering to much-divided apices c. 1 mm wide. Medulla of loose filaments, their cells 5–8 µm diam. [L:B 3–9], with occasional broader filaments 10–15 µm diam., these sometimes traversing between cortices. Cortex with 4–6 cell layers, in corymbose fascicles, the innermost branching often tri-quadrichotomous, then subsequent branching dichotomous. Inner cortical cells mostly subspherical, occasionally ellipsoidal, markedly shorter than medullary cells, 5–12 µm diam., becoming smaller towards the surface; outer cortical cells ellipsoidal to subspherical, 5–8 µm long, 3–7 µm diam. Vesicular cells ovoid to subspherical, occasionally pyriform, 25–40 µm diam., 35–50 µm long.

Reproduction. Spermatangia arising singly or in pairs on outer cortical cells, spherical, 2–3 µm diam. Other reproductive structures not observed.

Distribution. Known from tropical Indo-Pacific seas.

Habitat. Usually epilithic in the subtidal and associated with coral reefs.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 275 (2018)]