Ceramium affine Setch. & N.L.Gardner

Scientific Description

Habit and structure. Thallus pale red, with creeping prostrate axes, and simple or sparingly dichotomously branched erect axes to 1–2 mm tall arising from periaxial cells of the prostrate axes. Prostrate axes attached by multicellular rhizoids arising from periaxial cells. Erect axes with straight or slightly forcipate apices, pseudodichotomously branched every 7–18 cells, often with long unbranched segments. Nodal cortication with 4, rarely 5, periaxial cells, each cutting off 1 or 2 acropetal cells and occasionally a single oblique basipetal cell. Mature nodes 50–60 µm diam., 20–30 µm tall; axial cells to 40–60 µm diam. [L:B c. 3].

Reproduction. Spermatangia covering nodal cells for several distal segments. Tetrasporangia borne on periaxial cells, usually only 1 per node, pyriform to subspherical, 30–60 µm diam., including a thick hyaline wall, tetrahedrally divided, lacking an involucre. Female gametophytes and carposporophytes not seen.

Distribution. Widespread in warmer waters of the Indian and Pacific Oceans.

Habitat. Epiphytic on various algae in the intertidal to shallow subtidal.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 387–389 (2018)]