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Dryopteris intermedia
(Muhl. ex Willd.) A.Gray
Evergreen Wood Fern
Dryopteridaceae
Dryopteris intermedia is a species of fern in the family Dryopteridaceae. It is native to the northeastern United States and southeastern Canada, and is often cultivated.
Description
Dryopteris intermedia is evergreen, with leaves persistent through winter. Leaves are 3-pinnate-pinnatifid (bipinnate at the base) and ovate. Leaves are 32 to 90 cm long and 10 to 20 cm wide, on a stipe that is a third the length of the entire leaf. The stipe is covered with tan scales at the base. Leaflets are lanceolate-oblong; leaflets at the base of the leaf are not reduced in size. Pinnules (sub-leaflets) are longer on the side closer to the base of the leaf. Margins of the leaves have sharply pointed teeth. Sori are borne approximately in the center between the midvein and the margin (FNAEC 1993).
Dryopteris intermedia is similar to Dryopteris carthusiana and Dryopteris campyloptera, both deciduous fern species. Dryopteris intermedia has stems and indusia with glandular hairs, while those two species have few or no glandular hairs. For D. intermedia for the basal leaflet, the lowest basiscopic (closer to the base of the leaf) pinnule is shorter than the next pinnule farther out, but for D. carthusiana and D. campyloptera the lowest basiscopic pinnule is longer than the adjacent one. Also, in D. intermedia the lowest pinnule (sub-leaflet) is less than twice as long on the basiscopic side (closer to the base of the leaf) compared to the acroscopic side (on the upper side of the leaflet). For D. carthusiana and D. campyloptera the lowest pinnule is more than twice as long (“Dryopteris: Dichotomous Key”).
Dryopteris intermedia is similar to Dryopteris carthusiana and Dryopteris campyloptera, both deciduous fern species. Dryopteris intermedia has stems and indusia with glandular hairs, while those two species have few or no glandular hairs. For D. intermedia for the basal leaflet, the lowest basiscopic (closer to the base of the leaf) pinnule is shorter than the next pinnule farther out, but for D. carthusiana and D. campyloptera the lowest basiscopic pinnule is longer than the adjacent one. Also, in D. intermedia the lowest pinnule (sub-leaflet) is less than twice as long on the basiscopic side (closer to the base of the leaf) compared to the acroscopic side (on the upper side of the leaflet). For D. carthusiana and D. campyloptera the lowest pinnule is more than twice as long (“Dryopteris: Dichotomous Key”).
Uses
Note: Please see the disclaimer regarding any information about medical or edible uses.
Dryopteris intermedia is used as an ornamental. It prefers moist, humusy, well-drained soils in part to full shade, and grows in USDA zones 5 to 8 (MBG).
Distribution
Dryopteris intermedia is found in moist rocky woods, and is particularly associated with hemlock (Tsuga) forests or the edges of swamps. It is native from southern Ontario east to Newfoundland, south to northern North Carolina, west to northeastern Arkansas (FNAEC 1993).
Status
References
Dryopteris: Dichotomous Key. 2019. [accessed 2021 May 20]. https://gobotany.nativeplanttrust.org/dkey/dryopteris/#all
FNAEC (Flora of North America Editorial Committee), editor. 1993. Flora of North America, north of Mexico. Volume 2: Pteridophytes and Gymnosperms. New York: Oxford University Press.
MBG (Missouri Botanical Garden), Dryopteris intermedia. Plant Finder. [accessed 2021 May 20]. http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=285664
FNAEC (Flora of North America Editorial Committee), editor. 1993. Flora of North America, north of Mexico. Volume 2: Pteridophytes and Gymnosperms. New York: Oxford University Press.
MBG (Missouri Botanical Garden), Dryopteris intermedia. Plant Finder. [accessed 2021 May 20]. http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=285664
Description
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