Dryopteris intermedia
intermediate wood fern
Family: Dryopteridaceae

basal pinnae

Fronds of Dryopteris intermedia range from 30-90 cm in length, and most healthy plants in our area are at least 40 cm long. The blades are clearly longer than wide and 3 pinnate-pinnatifid. Tan scales are conspicuous at least at the base of the stipe.

Dryopteris intermedia and D. carthusiana are similar in general appearance and both are common. For D. carthusiana the lower basal pinnule of the lowest pinna is longer than the adjacent pinnules, and it is shorter than the adjacent pinnules in D. intermedia. Some fronds are difficult to place on this basis and it is wise to look at a large sample of leaves if there is any question. Fronds of D. intermedia are evergreen and those of D. carthusiana are not, a character that is very helpful in winter and spring. Glands on the indusia and midribs of blade segments of D. intermedia are a good character, but they can be difficult to see, tend to wear off as the fronds age and generally require a good hand lens or dissecting scope for observation. There are no glands on D. carthusiana.

D. intermedia ranges across the northeastern United States and Eastern canada, south to North Carolina and Tennessee and west to Missouri, Minnesota and Ontario. It is found throughout Wisconsin, but appears to be more common in the north. Habitats include a variety of forests, including swamps, though that is not as common.

Key to Ferns

Introduction to Ferns

Glossary of terms

List of all Pteridophytes

Explanation of page features

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