Tiffaniella cymodoceae (Børgesen) Gordon-Mills

Scientific Description

Habit and structure. Thallus medium to dark red-brown, forming spreading tufts on the hosts, 3–7 mm high, with prostrate filaments bearing subdichotomous erect filaments. Attachment of prostrate filaments by digitate haptera; epiphytic on Codium galeatum and C. laminarioides. Structure. Prostrate filaments 40–90 µm in diameter, cells L/D 2–3.5; erect filaments tapering only slightly, median cells 30–90 µm in diameter and L/D 3–7.5. Cells multinucleate; rhodoplasts discoid.

Reproduction. Gametophytes dioecious or monoecious. Female axes usually lateral, 4–5(–13) cells long, the last 4 cells short and the fifth 4–5 times as long as the fourth cell. Subapical cell with 3 periaxial cells, one sterile, one fertile and cutting off an auxiliary cell, and the other (supporting) cell bearing a terminal sterile cell and lateral involucral filaments before or after fertilization. Post-fertilization the carpogonial branch cells fuse and both auxiliary cells are involved in the two-armed fusion cell, which cuts off small gonimoblast cells and ovoid terminal carposporangia 20–45 µm in diameter, without any involucral branchlets. Spermatangial heads are 30–50 µm in diameter and L/D 2–3, sessile or on short pedicels on upper parts of erect filaments. Tetrasporangia are clustered on short pedicels on upper parts of erect filaments, 40–50 µm in diameter, undivided in Australian collections.

Distribution.Mauritius, South Africa. Shark Bay, W. Aust., to Seal Bay, Kangaroo I., S. Aust.

[After Womersley, Mar. Benthic Fl. Southern Australia IIIC: 214–216 (1998)]