| Diagnosis |
Large, dark brown thalli attached to substrate by a discoid holdfast; a short (less than 1 cm) and slender stem, giving rise to 1 or 2 main somewhat compressed and smooth primary branches. Branchlets bearing leaves and vesicles alternately arranged on the primary branches; leaves generally oblong (2.5 to 3.5 cm long) and obovate (2.0 to 3.0 cm long), with coarsely toothed outer margins, cryptostomata scattered on both surfaces; distal portions of some leaves with thick duplicate margins. Vesicles sparse, pedunculate, attached to the stalk of the leaves, elliptical to spherical, 4 to 11 mm in diameter, with isolated lateral teeth or ridges, sometimes with foliaceous extensions. Receptacles forming simple to compound cymes with short stalks; receptacular branches once or twice branched, compressed to flattened at their distal portions with teeth at tips and margins. Thalli up to 50 cm in height (Ref. 80758). |
