| Diagnosis |
Thalli large, dark brown to yellowish brown, attached to rocks by a coarse branching holdfast; stem short cylindrical. Primary branches terete, bearing irregularly alternate secondary branches with numerous simple and Y-shaped proliferations. Mature thalli with fewer and smaller oblanceolate leaves, 7 to 15 mm long and 1.5 to 4 mm wide, with coarsely dentate or serrated margins; midrib prominent up to near the apex. Cryptostomata scattered on the surface of leaves. Stalked vesicles ovate or spherical, numerous; vesicles attached to the secondary, tertiary and terminal branches either singly or in clusters, 1.0 to 2.5 mm in diameter, bearing few cryptostomata and/or teeth-like structures. Plant dioecious. Male receptacles racemose-paniculate, receptacular branches terete, warty. Female receptacles small, cymose; receptacular branches short, dense, compressed, simple or forked with teeth or spines at margins. Thalli up to 40 cm in height (Ref. 80758). |