Griffithsia balara Baldock

Scientific Description

Habit and structure. Thallus light to dark red, 8–14 cm high, irregularly branched with long axes bearing whorled laterals of limited growth, densely clothed below with anastomosing rhizoids. Attached by rhizoids; epilithic. Structure. Axial cells cylindrical, 350–410 µm in diameter and L/D 2.5–4.5, most bearing from their upper shoulders a whorl of 4 lateral subdichotomous tufts produced sequentially and branched 1–3 times, occasionally bearing whorls of 4 laterals, the basal cells narrow-cylindrical, swollen distally, 180–210 µm in diameter and L/D 7–9; filament apices narrowing markedly, apical cells conical. Rhizoids robust, unbranched, arising from the lower parts of axial cells, intermingling with laterals and forming characteristic rope-like masses 7–12 mm in diameter.

Reproduction. Gametophytes unknown. Tetrasporangia globose, 50–70(–90) µm in diameter, produced successively in groups of 3–6 on fascicles consisting of 1(–2) minute, terete cells developed in masses from the shoulders of inflated cells of long axes and from the subapical cells of many lateral branch tufts, tetrahedrally divided; apical cell above each mass of fascicles becoming ovoid, and producing a narrow filament of 1–2 cells that rarely divides subdichotomously; vegetative cell bearing the fascicles enlarging greatly, becoming pyriform, 530–700 µm in diameter and producing from its upper shoulders a whorl of 16–18, incurved, 1-celled branches 130–150 µm in diameter and L/D 2.5–5, enclosing the masses of fascicles in a palisade-like involucre; vegetative filament above mature fascicles commonly lost, resulting in a cupulate structure.

Distribution.Hopetoun, W. Aust., and W of Flinders I., S. Aust., 32 m deep.

[After Womersley, Mar. Benthic Fl. Southern Australia IIIC: 335 (1998)]