Lophocladia kuetzingii (Kuntze) P.C.Silva

Scientific Description

Habit and structure. Thallus medium to dark red-brown, 5–15 cm high, much branched irregularly radially with one to several axes or main branches, laterals mostly erect, upper and mid branches clothed with rhodoplastic trichoblasts, apices often congested. Attachment by rhizoids with multicellular discs, from prostrate or erect basal parts. Structure. Pericentral cells 4, branch axes 60–100 µm in diameter near apices, 300–600 µm in diameter in mid parts, and lower axes 0.5–1.5 mm in diameter. Trichoblasts 2–5 mm long, arising just below apices on a one quarter spiral, irregularly basally branched (not complanately) 2–4 cells apart, slender, 15–25 µm in diameter, cells L/D (5–)10–20; adventitious filaments absent. Lateral branches replacing trichoblasts. Cortication slight above around the large, clear, pericentral cells, becoming thicker on older axes. Cells multinucleate, few in trichoblast cells; rhodoplasts discoid, crowded.

Reproduction. Gametophytes dioecious. Procarps borne on the second segment (which becomes polysiphonous) of trichoblasts. Carposporophytes with a basal fusion cell and much branched gonimoblast with clavate terminal carposporangia 25–45 µm in diameter. Cystocarps ovoid to urceolate, 600–800 µm in diameter, with a short, corticated, stalk and a very slight neck; pericarp ostiolate, 2 cells thick, corticated only near the base. Spermatangial organs without trichoblasts, on monosiphonous pedicels with short sterile apical filaments, 180–650 µm long and 40–80 µm in diameter. Tetrasporangial stichidia slightly spirally twisted, without trichoblasts, occurring as a basal branch of a trichoblast with a monosiphonous pedicel 2–4 cells long, 400–1000(–1500) µm long and 60–100 µm in diameter. Tetrasporangia one per segment, spirally arranged, 40–80 µm in diameter, with 3 elongate cover cells.

Distribution.Warmer western and eastern coasts of Australia, and from American R. inlet on Kangaroo I., S. Aust. N Papua New Guinea.

Habitat. L. kuetzingii appears to be confined to sheltered waters on the Australian coast.

[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 249–250 (2003)]