Dryopteris intermedia A. Gray, the intermediate wood fern, is an evergreen eastern North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

n species also occasionally found in Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

. It is a diploid species, and is the parent of several species of hybrid origin, including Dryopteris carthusiana

Dryopteris carthusiana

Dryopteris carthusiana H.P. Fuchs is a species of fern native to damp forests throughout the Holarctic Kingdom...

.

This fern is often confused with several other wood fern species, including D. carthusiana, D. campyloptera

Dryopteris campyloptera

Dryopteris campyloptera, also known as the mountain wood fern, is a large American fern of higher elevations and latitudes. It was once known as Dryopteris spinulosa var. Americana. This species also has been referred to as D. austriaca and D. dilatata...

, and D. expansa

Dryopteris expansa

Dryopteris expansa, alpine buckler fern or spreading wood fern, is a species of fern native to cool temperate and subarctic regions of the Northern Hemisphere, south at high altitudes in mountains to Spain and Greece in southern Europe, to Japan in eastern Asia, and to central California in North...

. It especially extensively shares the range of D. carthusiana, but the two may be distinguished by the innermost pinnule on the bottom side of the bottom pinna: this pinnule is longer than the adjacent pinnules in D. carthusiana, but shorter or even in D. intermedia.