Schizymenia dubyi (Duby) J.Agardh
Species genera et ordines algarum 171 (1851)
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-brown, mucilaginous, foliose, simple to variously and irregularly lobed, often lacerate from above (sometimes to the base), margin smooth to somewhat ruffled, 10–60 cm high and 5–15 cm broad with branches (1–)2–10 cm broad, 300–600(–1000) µm thick, base cuneate, usually expanding fairly abruptly from a narrow stipe. Holdfast discoid, 1–3 mm across, with one to a few fronds; epilithic. Structure of a cortex 60–100 µm thick, of discrete branch systems (6–)8–10 cells long, inner cells subspherical to ovoid, 6–10(–14) µm in diameter, with tapering to elongate outermost cells 2–4 µm in diameter, L/D (1–)1.5–2. Gland cells usually but not always present in outer cortex, ellipsoid-ovoid to clavate, 14–30 µm long and 6–10 µm in diameter, with granular contents. Medulla of moderately dense entangled filaments 3–5(–10) µm in diameter. Rhodoplasts several per cell, discoid to elongate.
Reproduction. Sexual thalli monoecious. Carpogonial branches 3-celled with a relatively straight trichogyne, borne on an inner cortical cell, with the supporting cell cutting off a 1–2-celled sterile row; adjacent cells staining darkly and also cutting off sterile cells. Carposporophyte produced from an inner cortical (auxiliary?) cell, 100–240 µm across and more or less ovoid with relatively few ovoid carposporangia 15–20 µm in diameter, protruding into the medulla and with a distinct depressed ostiole through the cortex. Spermatangia developed on outer cortex, elongate and tapering outwardly, 2–3 µm in diameter and L/D 3–4, cutting off ovoid spermatia. Tetrasporophytes crustose, with erect filaments producing zonately divided tetrasporangia (unknown in southern Australia).
Distribution. Europe, Mediterranean, Japan. In southern Australia, Fremantle, W. Aust., and Pondalowie Bay, S. Aust., to Point Lonsdale, Vic.
[After Womersley, Mar. Benthic Fl. Southern Australia IIIA: 280–281 (1994)]
