[Illustration:  Sori of Sensitive Fern]

[Illustration:  Sensitive Fern. Onoclea sensibilis]

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

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

(2) OSTRICH FERN

Onoclea struthiopteris.  PTERETIS NODULOSA

Struthiopteris Germanica. Matteuccia struthiopteris

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

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

The rootstocks send out slender, underground stolons which bear fronds the next year.  Sterile fronds appear throughout the summer, fertile ones in July.  Seen from a distance its graceful leaf-crowns resemble those of the cinnamon fern.  An intermediate form between the fertile and sterile fronds is sometimes found, as in the sensitive fern.  This handsome species thrives under cultivation.  For grace and dignity it is unrivaled, and for aggressiveness it is, perhaps, equaled only by the lady fern.  For the climax of beauty it should be combined with the maidenhair.  The ostrich fern is fairly common in alluvial soil over the United States and Canada.

[Illustration:  Sori and sporangia of Ostrich Fern]

II

THE FLOWERING FERN FAMILY

OSMUNDACEAE

This family is represented in North America by three species, all of which belong to the single genus.

OSMUNDA

The osmundas are tall swamp ferns growing in large crowns from strong, thickened rootstocks; the fruiting portion of the fertile frond much contracted and quite unlike the sterile.  Sporangia large, globular, short-stalked, borne on the margin of the divisions and opening into two valves by a longitudinal slit.  Ring obscure. (From Osmunder, a name of the god Thor.)

(1) FLOWERING FERN, ROYAL FERN

Osmunda regalis.  Osmunda regalis, var.  SPECTABILIS

Fronds pale green, one to six feet high; sterile part bipinnate, each pinna having numerous pairs of lance-oblong, serrulate pinnules alternate along the midrib.  Fruiting panicle of the frond six to twelve inches long, brown when mature and sometimes leafy.