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.