Scinaia tsinglanensis C.K.Tseng

Scientific Description

Habit and structure. Thallus medium red to red brown, 3–10 cm high, subdichotomously branched every (2–)5–20 mm, constricted or not at the branchings, branches 0.5–2 mm in diameter, cylindrical, with bluntly pointed apices. Holdfast discoid, 1–2 mm across; epilithic. Structure multiaxial, developing a central core of slender, branched, entwined filaments 2–4(–8) µm in diameter, from which radiate dichotomous medullary filaments terminating in 2–3 ovoid rhodoplastic cells 8–12 µm in diameter, with an outer layer of colourless utricles, polygonal in surface view, 25–35 µm long and 18–25 µm in diameter.

Reproduction. Sexual thalli monoecious. Monosporangia cut off from elongate rhodoplastic cells penetrating between the hypodermal cells. Carpogonial branches 3-celled, developing on outer medullary filaments, with the hypogynous cell cutting off two sterile branches, 1-celled and 2-celled, and the basal cell producing 3–4 sterile branches which form the involucre after fertilization. Fertilized carpogonium cutting off several initials forming branched gonimoblast filaments with chains of ovoid to clavate carposporangia 10–15 µm long and 4–7 µm in diameter; fusion cell present. Cystocarps 200–300 µm in diameter, ostiolate, with a well developed involucre. Spermatangial filaments scattered or in dense sori, arising from hypodermal cells and penetrating between the utricles, with terminal ovoid spermatangia 2–4 µm in diameter.

Distribution. On all Australian coasts. China.

Habitat. Coasts with moderate to slight water movement, usually 3–30 m deep.

[After Womersley, Mar. Benthic Fl. Southern Australia IIIA: 103–105 (1994)]