Plants floating or rooted. Sterile leaves lanceolate to deltate to ovate. Petiole of sterile leaf 1--11 cm, not inflated; small leaves lobed to pinnate, segments or pinnae with entire to somewhat incised margins, larger leaves 2-pinnate-pinnatifid with deeply incised pinnae. Blade of sterile leaf 3--16 × 2.5--17 cm, pinnae deltate to ovate; proximal pinnae usually alternate. Fertile leaves lanceolate to deltate to ovate to 19 × 12 cm. Petiole of fertile leaf 6--9 cm. Blade of fertile leaf 2--3-pinnate; terminal segments narrow. Sporangia scattered to densely crowded between midvein and revolute margin, with 20--40 or more indurate annulus cells. Spores 16 per sporangium, 107--150 µm diam. 2 n = 78.
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