Dennstaedtiaceae

Deciduous ferns arranged in rows and often forming dense colonies from creeping and forking underground stems (rhizomes), and with spore-producing structures (sori) on the underside of the leaves along the leaflet edges.

Spore-producing structures are tiny, round and situated on the upper margin of the underside of the leaflets, covered with a cup-shaped protective membrane (indusium) and partly covered by teeth that are on the edges of the leaflets and abruptly bent down (Hay-scented Fern), or are linear and very close to one another or confluent, and covered by a minute nearly obsolete transparent or translucent membrane (inner indusium) and the under-rolled leaf margin (outer false indusium).

Leaves are medium-sized, delicate, soft, and thin, and have a hay-like fragrance when crushed, or are huge, arranged in threes, firm and tough. Leaves are divided once to three-times, and are smooth or slightly hairy, or minutely glandular-hairy underneath.

The above ground and underground portions of the stems have hairs rather than scales.