Resembling no. 5 [Thelypteris palustris Schott]; petioles of the sterile blades to 2 dm, of the fertile to 3.5 dm, mostly a little shorter than the blades; blades a little narrower, to 5 × 1.5 dm; costae and veins only sparsely or scarcely hairy; veins simple, those of the sterile segments 4–5 pairs, of the fertile ones 6–7 pairs; indusia margined with minute glands; 2n=128. Swamps and moist woods, in acid soil; N.S. to Va. and W.Va.; disjunct in the driftless area of Wis. (Aspidium s.; Dryopteris s.)