Plant floating or partly submerged, usually anchored in soil, the roots borne on the stipe. Leaves very thin, simple, dimorphic, usually glabrous; sterile leaves +/- pentagonal, to 25 cm long, about as broad, expanded at about the middle and deeply divided (appearing 2-4-pinnatifid), the ultimate segments mostly 3-10 mm broad, blunt to rounded at apex; leaves of floating plants usually with bulbous stipes; fertile blades to 40 cm long, divided as in sterile blades but with segments more than 2 mm wide, the margins evenly and narrowly revolute. Sporangia large, globose, borne in 1 row along each margin. Shattuck 606. Collected once by Shattuck; not collected on BCI in recent years, but probably still occurs there. Seen fertile in July.