Perennial fern 30 - 80 cm tall Leaves: clustered, stalked, green, narrow, twice pinnately compound, typically hairless on upper surface, but glandular on lower side of main "midrib" (rachis), which also has lengthwise groove on upper surface. Rhizome: short-creeping to somewhat erect, scaly. Spores: misshapen, sterile.
Similar species: Dryopteris x boottii is most similar to its two parent species, D. intermedia and D. cristata. The distinguishing characteristics of the hybrid are that it has twice pinnately compound leaves with glandular hairs on the rachis and pinnae "midribs" (costae) and flaps of tissue over the spore clusters (indusia) as in D. intermedia, but narrow leaf blades with the lowest leaf divisions (pinnae) being triangular and usually shorter than those above, as in D. cristata. It also only produces sterile, misshapen spores.
Habitat and ecology: Observed occasionally in wetter woods in our eastern counties.
Occurence in the Chicago region: native
Notes: This is a sterile hybrid between Dryopteris intermedia and D. cristata.
Etymology: Dryopteris is from the Greek drys (oak), and pteris (fern) referring to the plant's habitat. Boottii is named after one of several botanists from the 1800's with the surname Boott.
Author: The Field Museum
From Flora of Indiana (1940) by Charles C. Deam
I reported this fern from Noble and Wells Counties but I now refer my specimens to other species. R. M. Tryon, Jr. has found it in La Porte and Porter Counties. His determinations have been checked by fern specialists. This species is regarded by some fern students as a hybrid between Dryopteris cristata and Dryopteris spinulosa var. intermedia.