486 FILICES. Struthiopteri«. 



2. STRUTHIOPTERIS. Willd. sp. 5. p. 288 ; J. Smith, I.e. no. 47. ostrich-fern. 

 [From the Greek, strovihos, an ostrich, and pteris, a fern ; the fronds somewhat resembling the plumes of that bird,] 



Fertile fronds contracted ; their margins revolute, connivent, forming a general involucre. Sori 

 round, confluent, naked ; the pedicels of the capsules cohering at the base, forming an 

 elevated thickened receptacle. — fronds large, bipinnatifid ; the fertile pinns linear, revo- 

 lute, moniliform, each segment producing 5 pinnate free veins, bearing clusters of capsules 

 at their extremity ; the margin of the segments incurved and lacerate. 



1. Struthiopteris Germanica, Willd. Common Ostrich-fern. 



Willd. I. c. ; Beck, hot. p. 456 ; Hook. fl. Bor.-Am. 2. p. 262. S. Pennsylvanica, Willd. 

 I. c. ; Pursh, fl, 2. p. 666 ; Bigel. fl. Bost. p. 392 ; Torr. compend. p. 385. Osmunda 

 Struthiopteris, Linn. sp. 2. p. 1066. Onoclea Struthiopteris, Schk. Fil. t. 105, and O. nodu- 

 losa, ejusd. t. 104, fide Hook. O. nodulosa, Michx. fl. I. p. 272? 



Sterile fronds 2-3 feet high, forming tufts ; the pinnae numerous, deeply pinnatifid, sessile ; 

 segments entire, rather acute ; the veins pinnate, unconnected : stipe smooth and angular. 

 Fertile fronds shorter than the sterile, but with a thicker stipe. Pinnae very numerous and 

 crowded, 1-2 inches long, almost terete when dry ; the segments incurved, and filled with 

 the confluent sori. Pedicels of the capsules persistent, united below, and forming a thick 

 brush-like elevated stalk or receptacle. 



Low grounds, and borders of rivers, in rich soil ; western part of the State : rare. Fr. 

 July- August. The North American plant is considered distinct from the European by some 

 botanists, but I agree with Beck and Hooker in regarding them as one species. 



3. ALLOSORUS. Bernh. ; J. Smith, I. c. no, 7. allosorus. 



[From the Greek, alios, varioas, and soros, a heap ; probably in allusion to the changing appearance of the sori at 



different ages of the plant.] 



Cryptogramma, if. Br. 

 Sori round or oblong, at first distinct, at length laterally confluent, forming a broad intra- 

 marginal compound transverse sorus. — Fronds bi-tripinnate ; the fertile ones contracted : 

 margins free, revolute, connivent, forming a general involucre. Veins forked, free, bearing 

 the capsules at their apices. 



I. Allosorus gracilis, J. Sm. Slender Allosorus. 



Frond lanceolate, smooth ; the sterile pinnate, with pinnatifid divisions and few broadly ovate 

 obtuse segments ; the fertile bipinnate, with linear-oblong acute somewhat crenate segments ; 

 rachis smooth. — J. Smith, I. c. Pteris gracilis, Mich. fl. 2. p. 262 ; Pursh, fl. 2. p. 668 ; 

 Beck, hot. p, 454 ; Hook, fl. Bor.-Am. 2. p. 264. Cheilanthes gracilis, Spreng. 



