484 FILICES. PoLv PODIUM. 



'•" AspiDlES. Sori roundiBh. Involucres orbicular or reniform ; either peltate or attached to the inner side of the receptacle, sometimes 



calyciform and including the capsules. 



12. AsPiDiUM. Sori round, seated on the middle or extremity of the veinlets. Involucre peltate or reniform. Fronds 



1 - 3-pinnate : veins forked ; the veinlets (in N. Amer. species) free. 



13. O.vocLEA. Fertile frond contracted ; the segments incurved and globose, constituting a general involucre. Sori 



4-6, confluent, each with a proper cucullate involucre. 



14. WooDSiA. Sori round. Involucre calyx-like, open at the top ; the margin irregularly lobed or fringed with hairs. 



15. Cystopteris. Sori round, minute. Involucre lateral, oblong-reniform, inflated, cucullate. Veins forked ; the 



veinlets free. 



• •>.> DJCKSONIE.E. Sori marginal, globose or obloner, furnished with a special involucre, which is attached to the inside of the sorus, and is 



combined with the altered margin of the frond. 



16. DiCKSoNiA. Sori arising from the apex of a vein. Involucre 2-valved or entire, sometimes cup-shaped. 



• PoLYPODiF..*, J. Sm. Sori round or elongated, without a partial involucre. 



1. POLYPODIUM. Linn.; J. Smith, gen. Ferns, in Hook. jour. hot. 4. p. 46. 



POLYPODY. 



[From the Greek, polys, many, and pous, foot ; from the numerous feet-like branches of the root-stock.] 



Sori roundish, scattered on the under surface of the frond. Indusium none. — Ferns of 

 various habit. 



* Frond pinnatifid. 



1. PoLYPODiuM vuLGARE, voT. Americanum, Hook. Common Polypody. 



Frond deeply pinnatifid, smooth ; segments hnear-oblong, obtuse, crenate-serrulate ; sori 

 large, distinct. — Hook. fl. Bor.-Am. 2. p. 208. P. Virginianum, Linn. sp. 2. p. 1085. 

 P. vulgare, Bigel. fl. Bast. p. 388 ; Torr. compend. p. 380 ; Beck, bat. p. 447 ; Darlingt. 

 fl. Cest. p. 575. 



Rhizoma thick, creeping, branched, scaly. Fronds 6-10 inches long, somewhat coriaceous, 

 smooth, growing in thick patches, 1 i - 2 inches wide : segments mostly alternate, 3-4 lines 

 wide, slightly crenate or serrate. Sori nearly a line in diameter, distinct when young, but at 

 length touching each other. 



Rocky woods and hill-sides : common. Fr. July - August. The American plant differs 

 from the European only in the fronds being narrower and more oblong, the segments more 

 distant, and the sori nearer the margin. 



♦• Frond Inpinnatifid. 



2. PoLYPODiuM Phegopteris, Linii. Beech Polypody. 



Frond bipinnatifid, the two lower pinnae deflexed ; segments linear-oblong, obtuse, entire, 

 ciliate, the lower ones adnate-decurrent ; veins hairy ; sori mostly solitary, marginal ; stipe 

 retrorscly pubescent. — Linn. sp. 2. p. 1089 ; Engl. hot. t. 224 ; Beck, hot. p. 447 ; Hook, 

 fl. Bor.-Ain. 2. p. 258 (var. minus). P. connectile, Michx. fl. 2. p. 271 ; Willd. sp. 5. p. 

 200 ; Pursh, fl. 2. p. 659 ; Bigel. fl. Bost. p. 389 ; Torr. compend. p. 380. 



