Curdiea angustata (Sond.) A.Millar

Scientific Description

Habit and structure. Thallus medium to dark red-brown, 20–60 cm high, drying cartilaginous, 0.5–1(–1.5) mm thick, complanately, marginally and irregularly branched, often with marginal proliferations (sometimes mostly unilateral), main branches 5–30(–50) mm broad, lesser branches and proliferations usually 2–10 mm broad and 1–4(–8) cm long, usually basally constricted. Holdfast discoid, 2–10 mm across, with one to a few stipes; epilithic. Structure multiaxial, pseudoparenchymatous throughout, with a cortex 2–4 cells thick, outer cells 3–6 µm in diameter and L/D 1–2, becoming thicker below with anticlinal rows of elongate cells, grading inwards to a medulla of large ovoid cells 80–150 µm in diameter with thick walls (becoming 15–25 µm thick) and numerous, prominent, secondary pit-connections. Rhodoplasts discoid, numerous per cell.

Reproduction. Gametangial thalli dioecious. Female plants with 2-celled carpogonial branches borne near branch margins on mid cortical supporting cells with closely adjacent cortical filaments. Carposporophytes with a dense gonimoblast reticulum and small basal fusion cell(s), producing a dense upper mass of erect gonimoblast filaments terminating in straight chains of numerous subspherical to ovoid carposporangia 10–14 µm in diameter, maturing apically. Cystocarps marginal, usually in long series, prominent, globose, sessile or slightly basally constricted, 1–1.5 mm across; pericarp massive, with inner tangentially elongate cells (continuing around base of the carposporophyte) and a medulla and cortex similar to the vegetative tissue, with a small ostiole lined by short cells cut off from the medullary pericarp cells. Spermatangia in surface sori, cut off via elongate initials from outer cortical cells. Tetrasporangial nemathecia shallow, inconspicuous, on upper branches; tetrasporangia basally pit-connected to subapical cells of 4–5-celled paraphyses 100–140 µm long, end cells clavate and 3–8 µm in diameter, sporangia clavate to ovoid, 20–25 µm long and 10–15 µm in diameter, cruciately divided.

Distribution.Hamelin Bay, W. Aust., to Collaroy, N.S.W. and around Tas. New Zealand (?).

Habitat. C. angustata usually occurs in deep-water on rough-water coasts.

[After Womersley, Mar. Benthic Fl. Southern Australia IIIB: 39–41 (1996)]