Myriodesma serrulatum (J.V.Lamour.) Endl.
Gen.Pl. 148 (1843)

Conservation Code: Not threatened
Naturalised Status: Native to Western Australia
Name Status: Current

Distribution

Beard’s Provinces: South-West Province.

IBRA Regions: Jarrah Forest, Swan Coastal Plain, Warren.

IBRA Subregions: Perth, Southern Jarrah Forest, Warren.

IMCRA Regions: Central West Coast, Leeuwin-Naturaliste, WA South Coast.

Local Government Areas (LGAs): Augusta Margaret River, Busselton, Capel, Cockburn, Dandaragan, Irwin, Jerramungup, Manjimup.

Scientific Description
John Huisman & Cheryl Parker, Thursday 8 September 2016

Habit and structure. Thallus medium to dark brown, 15–30 cm long, with usually two complanately branched fronds from the branched stipe. Holdfast discoid-conical; probably epilithic. Stipe 2–18 cm long, with 1–4 di- or trichotomies at intervals of 1–6 cm, each (1–)2–3 mm in diameter. Fronds 10–25 cm long, irregularly pinnate with long, alternate, laterals (2–)3–6(–10) cm long, 2–4(–5) mm broad, linear but tapering above, coarsely and regularly serrate along their length with teeth 1–1.5 mm long; denuded below; midrib present, inconspicous near apices. Structure of fronds 0.4–0.6 mm and 10–20 cells thick, with a medulla of elongate cells in older parts and a cortex of isodiametric cells with a surface phaeoplastic meristoderm.

Reproduction. Thalli monoecious. Conceptacles prominent, conspicuously raised above the surface, forming an irregular line on each side of midrib, bisexual, with a basal group of phaeophycean hairs and also sterile, simple or once-branched paraphyses; oogonia sessile, ovoid, 90–140 µm long and 60–80 µm in diameter; antheridia sessile or on branched paraphyses, elongate, 22–36 µm long and 8–15 µm in diameter.

Distribution. From Port Denison to Cape Riche, W. Aust.

[After Womersley, Mar. Benthic Fl. Southern Australia II: 410–412 (1987)]