Mychodea ramulosa J.Agardh

Scientific Description

Habit and structure. Thallus light to dark red, clumped, 10–20 cm high, with several to numerous erect axes from a stoloniferous base; axes slightly to moderately compressed, 2–4 mm broad, with laterals mainly from the margins but shorter laterals also from the surfaces, laterals terete to slightly compressed, with acute apices and not constricted basally. Holdfast consisting of stout haptera 2–3 mm across on the stolons; epilithic or epiphytic on various larger algae, seagrasses or tunicates. Structure uniaxial, with a prominent apical cell, developing a lacunate outer medulla and small-celled cortex similar to that in M. carnosa; outer cortical cells ovoid, 3–4 µm in diameter. Rhodoplasts elongate, ribbon like in inner cells.

Reproduction. Sexual thalli monoecious; procarpic; polycarpogonial. Carpogonial branches 3-celled, 2–6 borne on inner cortical cells which become auxiliary cells producing gonimoblast filaments with short chains of ovoid carposporangia 15–24 µm in diameter, lying within the matrix of gametophytic and gonimoblast filaments; enveloping tissue slight, with a cortical depression outside the carposporophyte. Cystocarps protruding, hemispherical, with the adjacent ramulus bent. Spermatangia in scattered sunken clusters in the outer cortex, similar to those in M. carnosa. Tetrasporangia scattered in the outer cortex, terminal, ovoid, 37–45 µm long and 20–25 µm in diameter, zonately divided.

Distribution.King George Sound, W. Aust., to Portland, Vic.

[After Womersley, Mar. Benthic Fl. Southern Australia IIIA: 456 (1994)]