Polystichum lonchitis (L.) Roth
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Rhizome erect or ascending; lvs 2–6 dm, the petiole very short; blade rigid, lance-linear, 3–7 cm wide, pinnate, gradually narrowed below; pinnae alternate, 25–40 pairs, lanceolate (the reduced lower ones subtriangular), acuminate, sharply auricled at the upper base, scaly beneath, darker green and scaleless above; fertile pinnae like the sterile; sori in a single row on each side of the midrib; indusium lacerate; 2n=82. Cool shaded rocks and hillsides, mostly on limestone; circumboreal, s. to N.S., Que., Ont., Mich., and Calif.