Dotyophycus abbottiae Kraft

Scientific Description

Habit and structure. Thallus 5.5–8.0 cm high, creamy white when fresh, rust-red when dried. Axes 1–2 mm in diameter, branched at intervals of 3–15 mm, calcified in outer medulla. Medullary filaments 10–25 µm in diameter, interspersed with rhizoids 5–6 µm in diameter. Cortical filaments c. 250 µm long; outer obovoid cells 15–18 µm in diameter; subsidiary filaments of narrower cells 4–8 µm in diameter, commonly with 1 or 2 slender deciduous hairs on outer cortical cells.

Reproduction. Spermatangia in clusters on outer cortical cells or on spermatangial mother cells arising from them. Carpogonial branches at first simple, 15–19-celled, all but distal 5–7 cells subsequently capable of producing 1–3 subsidiary protrusions, sterile filaments or carpogonial filaments, sometimes forming a compound carpogonial filament with up to 13 carpogonia. Cystocarps 400–500 µm in diameter, with terminal carposporangia 7–8 x 12–15 µm; sporangia regenerating within walls of previously shed sporangia. Fusion cell composed of carpogonium, hypogynous cell and distal 4 or 5 carpogonial filament cells, gonimoblast initials and cells of inner gonimoblast.

Distribution. Known only from the Pelsaert Group, Houtman Abrolhos and Rottnest I., W. Aust.

Habitat. Occurs on limestone overlain by a shallow layer of sand and coarse shell rubble.