Chondria transversalis Børgesen

Scientific Description

Habit and structure. Thallus forming sprawling clumps, to 2–3 mm tall, light red, with decumbent and erect axes, attached by clusters of rhizoids arising at intervals along the lower axes. Erect axes percurrent, sparingly branched laterally, with blunt apices and sunken tips. Trichoblasts borne near branch apices and in association with emergent lateral branches, dichotomously divided. All axes terete, bases of lateral branches slightly to markedly constricted, but otherwise the axes of similar width, 250–300 µm diam. Axial filament prominent throughout, with 5 pericentral cells, these each bearing 2 subcortical cells with a slightly larger diameter but half the length of the pericentral cells. Cortex with a single layer of smaller cells, in surface view hexagonal and somewhat equidimensional near apices, but becoming elongate when mature, 85–145 µm long, 15–30 µm broad.

Reproduction. Tetrasporangia borne in a spiral pattern embedded near apices of lateral branches, spherical, tetrahedrally divided, to 120 µm diam. (but possibly immature). Other reproductive structures not observed.

Distribution. Previously recorded from India and Queensland, but probably more widespread.

Habitat. Epilithic and epiphytic in the shallow subtidal.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 499 (2018)]