Key to Wisconsin Dryopteris

• 1a.Leaves less than 30 cm long and 6 cm wide, densely covered with large brown scales;indusia large and often overlapping; aromatic glands abundant; old leaves persisting asa conspicuous brown clump at plant base D. fragrans

• 1b.Well-developed leaves more than 30 cm long and 6 cm wide (except some sterile leaves of D. cristata), with only scattered scales; indusia rarely overlapping; glands lacking or sparse and not aromatic; old leaves not persisting more than a year, not forming dense clumps 2

• 2a.Sori borne at or very near the margin of the segments D. marginalis

• 2b.Sori medial or closer to the midvein of segments 3

• 3a.Blades 2--3 times pinnately compound, many of the pinnules deeply-lobed, with teeth ending in bristle-like tips 4

• 3b.. Blades once pinnately compound or lower pinnae divided into pinnules, but pinnules not deeply lobed and without triangular teeth ending in bristle-like tip (sharp teeth present at apex of lobes in D. cristata & D. clintoniana) 6

• 4a.Pinnule closest to the rachis on the lower side of the lowest pinna equal to or shorter than the pinnules next to it; blades relatively thin, remaining green through winter; glands scattered on indusia, rachis, and costae D. intermedia

• 4b.Pinnule closest to the rachis on the lower side of the lowest pinna larger than the pinnules next to it; blades slightly succulent, turning brown and shriveling in winter; glands absent 5

• 5a.Blades ovate-lanceolate; pinnule closest to the rachis on the lower side of the lowest pinna only slightly wider than the pinnule above it and slightly larger than the pinnule next to it; scales on petiole tan without a center stripe D. carthusiana

• 5b.Blades broadly triangular; pinnule closest to the rachis on the lower side of the lowest pinna as wide as the two pinnules above it and much larger than the other pinnules; scales on petiole dark brown or tan with a dark center stripe D. expansa

• 6a.Fronds widest at the middle, narrowed at the base, the lowest pinna less than half as long as middle pinnae; petioles less than 1/4 length of leaves; petioles and rachises with both scattered scales and hair-like scales D. flix-mas

• 6b.Fronds slightly wider at the middle, the lowest pinnae nearly as long as middle pinnae; all scales on petioles and rachis alike, not hair-like 7

• 7a.Lower and middle pinnae oblong-lanceolate, widest beyond the base; scales at base of petioles dark brown; sterile and fertile blades alike, dying in winter; sori closer to midvein than margin of segments D. goldiana

• 7b.Lower pinnae widest at base; scales at base of petioles dark brown; fertile leaves larger than sterile leaves; sterile leaves evergreen, persisting through winter; sori midway between midvein and margin of segments 8

• 8a.Fertile leaves about twice as tall as sterile leaves; pinnae of fertile leaves twisted perpendicular to the plane of the blade; lowest pinnae deltoid with 4--12 pairs of segments D. cristata

• 8b.Hypanthium glabrous, eglandular (rarely glandular). D. clintoniana