Gloiocladia australe (J.Agardh) R.E.Norris
Phycologia 592 (1991)
Conservation Code:
Not threatened
Naturalised Status: Native to Western Australia
Name Status:
Current
Scientific Description
John Huisman & Cheryl Parker,
Monday 20 June 2011
Habit and structure. Thallus medium to dark red to red-brown, fading to grey-red, (10–)20–40 cm high, soft and mucilaginous, complanately branched with flat, irregularly pinnate branches for 3–4 orders, main branches (3–)6–10 mm broad, bearing marginal pinnate branches 3–10 cm long and also simple branchlets 3–10 mm long, with ultimate branchlets 1–2 mm broad; compact, rounded, potentially adhesive, discs 2–3 mm across, terminate few to numerous branchlets. Holdfast discoid, with adhesions also by the discs of dense, elongate cells; usually epiphytic on sea-grasses or larger algae, or epilithic (?). Structure multiaxial, developing a cortex 50–90 µm thick of slender branched filaments 5–8 cells long, with the lower 2–3 cells irregular, 5–10 µm broad, and the upper 3–5 cells ovoid, 2–3 µm in diameter, arising from the lax inner cortex of ovoid cells 15–25 µm in diameter. Medulla 3–5 cells thick, cells large, ovoid, 60–200(–250) µm in diameter, with frequent secondary pit-connections. Hairs on outer cortical cells common. Rhodoplasts discoid to elongate in cortical cells, ribbon like in medullary cells.
Reproduction. Gametangial thalli monoecious. Carpogonial branches 4(?)-celled, borne on a relatively large globular supporting cell which also bears a 3-celled auxiliary cell branch, the upper auxiliary cell with a large spherical proteinaceous inclusion. Carposporophyte ovoid, 250–500 µm across, with an erect fusion cell with erect branches bearing lobes of ovoid carposporangia 20–25 µm in diameter. Basal nutritive tissue of short cells, pit-connected to the supporting cell and auxiliary initial cell, with erect filaments of prominent, persistent elongate cells around the carposporophyte and upper short-celled filaments around the ostiole. Cystocarps mostly marginal (also on the surface of broader branches), 0.7–1.5 mm across, with 2–4 horns, ostiolate. Spermatangia cut off from outer cortical cells, ovoid, 1–2 µm in diameter. Tetrasporangia scattered, or in nemathecia with extended cortical filaments, pit-connected to mid cortical cells, elongate ovoid, 16–24 µm in diameter, decussately divided.
Distribution. Point Peron, W. Aust., to Walkerville, Vic., and the N coast of Tas.
Habitat. G. australe is usually a deep-water species and commonly epiphytic on seagrasses.
[After Womersley, Mar. Benthic Fl. Southern Australia IIIB: 98–101 (1996)]
