Flora of New Zealand Series

Mostly aquatic ferns with creeping, branching rhizomes. Lvs arising at nodes, linear or with 2-4 ± obtriangular segments terminating a long stalk. Sporangia aggregated into sori, each containing both micro- and megasporangia, protected by indusia, and all enclosed in a hard sporocarp (modified lamina); annulus 0. Heterosporus, producing 1 megaspore per megasporangium and many microspores per microsporangium; spores lacking chlorophyll.

3 genera, almost cosmopolitan.