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Dryopteris Adanson. Woodfern, Shieldfern.

Key to Dryopteris

A genus of about 400 species, nearly cosmopolitan, but concentrated in temperate Asia. Sessa, Zimmer, & Givnish (2012) discuss the phylogeny and biogeography of Dryopteris; the clades shown in the key are from their work.

ID notes:Dryopteris and Athyrium are often confused when not fertile; they can be easily distinguished by breaking off a leaf and counting vascular bundles (which will appear as thread-like strands). Dryopteris has 5 and Athyrium has 2. Many Dryopteris species will hybridize with one another to form sterile hybrids. Whenever two or more Dryopteris species are found growing together, there is a good chance that hybrids are present. Hybrids generally show intermediacy between the two parents, and have abortive sporangia or spores.

Ref: Hoshizaki & Wilson (1999); Kees & Weakley (2018) In Weakley et al. (2018b); Kramer & Green (1990); Montgomery (1982); Montgomery & Paulton (1981); Montgomery & Wagner (1993) In Flora of North America Editorial Committee (1993b); Sessa, Zimmer, & Givnish (2012); Umstead & Diggs (2018); Wyatt (2020). Show full citations.

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Hover over a shape, letter, icon, or arrow on the map to see what it means. Data for arrows not developed for genera and families which may have species only occurring outside the flora area.

image of plant© Richard & Teresa Ware | Dryopteris celsa | Original Image ⭷
image of plant© Gary P. Fleming | Dryopteris carthusiana
image of plant© Alan Cressler: Dryopteris carthusiana, and Parathelypteris noveboracensis, Southern Appalachian Mountain Bog, North Carolina 1 by Alan Cressler | Dryopteris carthusiana source
image of plant© Louis Imbeau, some rights reserved (CC BY), uploaded by Louis Imbeau | Dryopteris filix-mas ssp. brittonii source | Original Image ⭷ Warning: was NOT research grade.
image of plant© Alan M. Cressler | Dryopteris cristata | Original Image ⭷