Millerella corallophila Huisman, G.H.Boo & S.M.Boo

Scientific Description

Habit and structure. Thallus forming a tangled clump, with prostrate axes bearing erect axes to 5 mm tall. Prostrate axes terete, 85–100 µm diam., attached by clusters of single-celled rhizoids. Erect axes simple or sparingly dichotomously branched, terete to compressed, 50–90 µm wide, mostly of similar breadth throughout, but tapering gradually to acute apices with a prominent apical cell. Medulla of longitudinal filaments visible from the surface, c. 5 µm diam. in erect axes, to 10 µm diam. in prostrate axes (broadest near attachment points). Cortex of pigmented cells 10–12 µm long and 5–7 µm wide in surface view, tending to be transversely elongate in prostrate axes, often transversely elongate in erect axes, but also irregularly shaped and arranged.

Reproduction. Tetrasporangia in simple or branched lanceolate stichidia borne at the apices of erect axes. Tetrasporangial stichidia to 780 µm long, 90–120 µm wide, with up to 31 fertile segments, these bearing whorls of up to 8 tetrasporangia, although typically only the distal segments bear sporangia, those proximal having been shed. Sporangia subspherical to ellipsoidal, 30–35 µm long, 20–25 µm diam. Other reproductive structures not observed.

Distribution. Known from Coral Bay and the Dampier Archipelago, W.A.; epilithic in the intertidal or shallow subtidal, sometimes associated with damsel fish territories

[After J.M. Huisman, G.H. Boo & S.M. Boo in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 258–260 (2018)]