Chondria succulenta (J.Agardh) Falkenb.

Scientific Description

Habit and structure. Thallus red to brown-red, 3–18(–30) cm high, much branched irregularly radially for 3–4 orders, usually with a main axis, branches terete, lateral branches initially constricted, axillary branching occasional; basal axes 0.6–2.5 mm in diameter, grading to lesser branchlets 500–800 µm in diameter. Holdfast discoid, 1–2 mm across, or attachment by haptera. Structure. Apices rounded or slightly depressed, with a protruding apical filament, pericentral cells relatively large, epidermal cells ovoid to elongate, (15–)20–25 µm in diameter and L/D 1.5–7(–12), with slight rhizoid development around the axial and pericentral cells in lower parts of the thallus; secondary cortex absent or slight near the base. Cell wall thickenings absent or present as hemispherical caps on upper ends of pericentral and inner cortical cells, the pericentral cells later also with a central band or girdle. Trichoblasts usually prominent. Cells with discoid to elongate rhodoplasts, chained in larger cells.

Reproduction. Gametophytes dioecious. Procarps on suprabasal cells of trichoblasts, with a 4-celled carpogonial branch and basal and lateral sterile groups. Carposporophytes with a basal fusion cell and branched gonimoblast with clavate terminal carposporangia 35–65 µm in diameter. Cystocarps ovoid to slightly urceolate, 0.7–1 mm in diameter, usually with a distinct basal spur; pericarp broadly ostiolate, 2 cells thick, ecorticate. Spermatangial plates discoid to slightly lobed, 400–650 µm across, with a single row of sterile marginal cells. Tetrasporangia near ends of lesser branchlets, on 2–3 pericentral cells per axial cell, 80–140 µm in diameter.

Distribution.Point Peron, W. Aust., to American R. inlet, Kangaroo I., S. Aust., probably Port Phillip, Vic., possibly N coast of Tas., and N.S.W.

Habitat. C. succulenta appears to be largely confined to sheltered inlets where there is strong current flow.

[After Womersley, Mar. Benthic Fl. Southern Australia IIID: 446 (2003)]