Onoclea Struthiopteris:—Caudex short, thick, erect, emitting slender subterranean stolons; stalks stout, a few inches to a foot long, chaffy at the base; fronds standing in a vase-like crown, dimorphous; sterile ones one to ten feet high, herbaceo-membranaceous, broadly lanceolate, narrowed from the middle to the base, abruptly short-acuminate, pinnate; pinnæ very many, sessile, the lowest ones sinuate and deflexed, the rest three to eight inches long, five to nine lines wide, linear-lanceolate, acuminate, deeply pinnatifid into numerous close-placed oblong obtuse entire segments provided with a midvein and several simple veinlets on each side; fertile fronds in the middle of the crown or vase, much shorter than the sterile, rigid, contracted, narrowed at the base, pinnate; pinnæ one to two inches long, crowded, obliquely ascending, linear, obtuse, sub-entire or pinnately lobed, the lobes one or two lines long and broad, the margins much recurved, and the whole pinna forming a somewhat articulated pod-like body; veinlets of the fertile segments few, soriferous on the back; receptacle elevated; indusium very delicate, lacerate-toothed, half surrounding the sorus; sporangia at length confluent and filling the fertile pinnæ. _Onoclea Struthiopteris_, Hoffmann, “Deutschlands Flora, p. 11 (1795).”—Swartz, Syn. Fil., p. 111.—Weber & Mohr, Taschenbuch, p. 47, t. iv., f. 3, 4.—Schkuhr, Krypt. Gew., p. 97, t. 105.—Mettenius, Fil. Hort. Lips., p. 97, t. xvii., f. 11-15.—Milde, Fil. Eur. et Atlant., p. 154. _Onoclea nodulosa_, Schkuhr, Krypt. Gew., p. 97, t. 104 (Perhaps also of Michaux, but this is still uncertain). _Onoclea Germanica_, Hooker, Sp. Fil., iv., p. 161.—Hooker & Baker, Syn. Fil., p. 46. _Osmunda Struthiopteris_, Linnæus, Sp. Pl., p. 1522. _Struthiopteris Germanica_, Willdenow, “Enum, p. 1071;” Sp. Pl., v., p. 288.—Link, Fil. Hort. Berol., p. 38.—Hooker, Fl. Bor.-Am., ii., p. 262.—Torrey, Fl. New York, ii., p. 486.—Gray, Manual, ed. i., p. 623, etc.—Koch, Syn. Fl. Germ. et Helv., ed. iii., p. 739.—Williamson, Fern-Etchings, t. 44. _Struthiopteris Pennsylvanica_, Willdenow, Sp. Pl., v., p. 289.—Pursh, Fl. Am. Sept., ii., p. 266.—Torrey, Compendium, p. 385.—Bigelow, Fl. Boston., ed. iii., p. 421. _Struthiopteris_, the genus only, Willdenow, in Berl. Mag., 1809, p. 160. Hab.—Low grounds, especially in fine alluvial soil subject to the overflow of rivers; from the Saskatchewan and Lake Winnipeg to New Brunswick, and southward to Pennsylvania and Illinois. Mentioned by Alexander Braun as coming from Arkansas. From Lapland to Sicily, and eastward to the Amoor region, Sachalin and Kamtschatka. Not known in the western parts of either Europe or America.