Tricleocarpa cylindrica (Ellis & Solander) Huisman & Borow.
Phycologia 164 (1990)
Conservation Code:
Not threatened
Naturalised Status: Native to Western Australia
Name Status:
Current
Scientific Description
John Huisman & Cheryl Parker,
Monday 20 June 2011
Habit and structure. Thallus (gametophyte) pale red to grey-red, 3–7 cm high, subdichotomously branched every 0.3–2.5 cm, branches terete, glabrous, 0.5–1.5 mm broad, occasionally regularly jointed. Holdfast discoid, 1–3 mm across; epilithic. Structure of a medulla of longitudinal filaments (3–15 µm in diameter) giving rise to radiating, dichotomously branched filaments that form the cortex of 3–4 layers of inflated cells, innermost 18–36 µm in diameter, somewhat longer than broad, grading to outer cortical cells 9–21 µm diameter, 5–6 sided in surface view. Rhodoplasts campanulate with a central pyrenoid. Calcification present in the cortex. Tetrasporophyte filamentous, the filaments approximately 25 µm in diameter.
Reproduction. Sexual thalli usually dioecious. Carpogonial branches 3-celled, arising near apices in place of vegetative filaments, with the hypogynous cell producing four large-celled branches and the basal cell four small-celled branches which develop into the involucre. Cystocarps subspherical, 200–300 µm in diameter, gonimoblast filaments directed both towards the surface of the plant and laterally, lining the involucre and intermixing with the involucral filaments, producing terminal, obovoid, carposporangia (25–30 µm long and 10–15 µm in diameter) from all faces of the involucre. After the release of carpospores, further sporangia are produced within the old sporangial wall. Male thalli with subspherical cavities 250–300 µm in diameter, with filaments bearing terminal or lateral, obovoid, spermatangia (6–8 µm long and 4–6 µm in diameter) projecting into the cavity. After release, further spermatia are produced within the old spermatangial walls. The tetrasporophyte with terminal or lateral, cruciately divided tetrasporangia, approximately 40 by 30 µm.
Distribution. Common in warmer waters. Hamelin Bay, W. Aust., around northern Australia to Dee Why, N.S.W.
[After Womersley, Mar. Benthic Fl. Southern Australia IIIA: 116–118 (1994)]
