Plants short-lived, rooted or floating. Stems erect, bearing a few thin scales. Leaves dimorphic, erect to spreading, with adventitious bud initials or small plantlets along margins; proximal leaves sterile, herbaceous, venation reticulate, without included veinlets; distal leaves fertile, larger than sterile leaves; segments revolute, covering sporangia. Sporangia abaxial, thin-walled, with mixed development, bearing 0--71 indurate annulus cells. Spores yellow, 16 or 32 per sporangium, 70--150 µm diam. Gametophytes terrestrial, green, asymmetrically cordate.