[Illustration: Sori of Sensitive Fern]

[Illustration: Sensitive Fern, Fertile and Sterile Fronds on one Stock Onoclea sensibilis (From the collection of Mr. and Mrs. L.P. Breckenridge)]
[Illustration: Sensitive Fern. Onoclea sensibilis]

[Illustration: Ostrich Fern. Onoclea Struthiopteris. Fertile Fronds]

(2) OSTRICH FERN

Onoclea struthiópteris. PTERETIS NODULOSA

Struthiópteris Germánica. Matteùccia struthiópteris

Fronds two to eight feet high, growing in a crown; broadly lanceolate, pinnate, the numerous pinnæ deeply pinnatifid, narrowed toward the channeled stipe. Fertile fronds shorter, pinnate with margins of the pinnæ revolute into a necklace form containing the sori.

[Illustration: Ostrich Fern. Sterile Fronds (New Hampshire)]