Dasya baillouviana (S.G.Gmel.) Mont.

Scientific Description

Habit and structure. Primary axes corticated, tapering to 300 µm diam. below the rounded apex. Pseudolaterals arising 1 per segment in a spiral pattern, dichotomously divided from the basal cell or suprabasal cell, then divided a further 2 or 3 times every 2 cells, then undivided for 17–20 cells. Basal and lower cells of pseudolaterals often corticated by rhizoidal cells arising from more distal cells, resulting in a hummock-like structure subtending the pseudolateral. Adventitious filaments present but not common, arising from cortical cells, similar in structure to pseudolaterals. Primary axes with 5 distinct pericentral cells. Cells of pseudolaterals 30–35 µm diam. near base, tapering to 15–20 µm diam. mid-branch, then to 10 µm below the apex.

Reproduction. Tetrasporangial stichidia with a 1–3-celled pedicel, arising from the main axes or the lower cells of pseudolaterals, rarely on more distal cells, with up to 12 fertile tiers, each with 5 tetrasporangia only partially covered by 2 or 3 cover cells. Proximal tiers usually empty as the sporangia are shed. Cover cells cuboidal to triangular in surface view, the lateral cover cells in each cluster transversely aligned. Tetrasporangia spherical, tetrahedrally divided, 30–37 µm diam. when mature. Other reproductive structures not seen.

Distribution. Widely distributed in tropical and warm seas.

[After J.M. Huisman in Algae of Australia: Marine Benthic Algae of North-western Australia, 2. Red Algae: 422–424 (2018)]