Cystopteris montana, previously classified as Athyrium montanum, is a species of fern known by the common name mountain bladderfern.

[1] It occurs throughout the high latitudes of the Northern Hemisphere, in Eurasia, Greenland, and Alaska, and around Canada.

The blades are borne on a petiole with a dark base and a light-colored end.

The blade is pentagonal in shape and divided into leaflets which are subdivided into many lobed and toothed segments.

[2][3] This fern grows in moist mountain habitat, such as forests near streams.