Usually dioicous, sometimes monoicous. Thallus closely adherent to the substratum rhizoids, pinnately branched and with stolons, this adherent thallus produces pinnate or subpalmate branches of limited growth which are ascending and loosely imbricated. Main axis 5-8 cells thick, branches 3-4 cells thick, 0.5-0.9 mm wide and 1.5-4 mm long, oblong-oblong-oval, widely and conspicuously winged with 3-5 rows of regularly hexagonal cells, about 15-20 x 20-30 µ, gradually increasing in size towards the middle, surface cells in the middle part of the branches 40-45 x 80-100 µ, the long axis of cells lying obliquely to the axis of the branch, so that the cells tend to form diverging rows. Gemmiferous branches rare, gemmae 2-celled, 40 x 50 µ. Interior cells of the branches in cross section 40-50 x 54-70 µ. Male branches often long, with up to 20 pairs of antheridia, margin lobed, only weakly crenate. Female branches deflexed, wing laciniate, the laciniae usually 2 cells wide and 4-5 cells long, incurved, crenate at apex or fimbriate with curved cells, usually with one or two small laciniae preceding the archegonia at the base of the branch.
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