450 CRYPTOGAMIA FILICE9. 



413. ASPIDIUM. Shield-fern. 



* Involucrum subumbilicate or reniform, attacked near the centre of ike 

 sorus and opening on all sides. 



t Fronds simply pinnate. 



A. acrostichoides : fronds pinnate ; segments lanceolate, falcate, acute, 

 ciliate-serrulate, auriculate on one side, at the base subsessile, only the 

 upper ones fructiferous ; sori at length confluent ; stipe chaffy. 



HAB. Shady rocks. Fronds 15 18 in. high ; seg. 1 inch long ; 

 fructiferous ones smaller. 



1 1 Frond subbipinnate. 



A. noveboracense : frond pinnate, the divisions pinnatifid, linear-lan- 

 ceolate ; segments oblong, obtuse, entire, ciliate ; sori marginal ; stipe 

 nearly smooth. 



HAB. Damp woods. July. Frond 1 2 feet high ; seg. mostly ob- 

 tuse, pubes. beneath. 



A. t.hclypteris : frond pinnate ; the divisions pinnatifid, linear-lanceolate, 

 distinct at the base ; segments ovate, acute, entire ; sori marginal, con- 

 tiguous, at length confluent. 



HAB. Wet woods and swamps. Frond afoot and a half high. Dis- 

 tinct from the preceding 1 



A. cristatum^: b. lancastriense : frond lanceolate-ovate, smooth, pin- 

 nate; divisions subcordate, pinnatifid ; segments triangular-oblong, 

 spinulose-serrate ; stipe nearly naked. 



1 1 1 Frond doubly and triply pinnate. 



A. marginale . frond bipinnate ; segments oblong, obtuse, decurrent, 



crenate, sinuate-repand at the base ; sori marginal ; stipe paleaceous. 

 HAB. Rocky places. July. Frond 18 in. high, very smooth ; invol. 



large, umbilicate. 

 A. d'datn.tum : fronds bipinnate ; divisions oblong ; distinct, incisely 



pinnatifid ; segments mucronately serrate ; stipe chaffy ; involucrum 



smooth. 

 HAB. Shady woods. July. Frond broad, 2 feet high ; stipe slightly 



chaffy. 



* * Involucrum oblong, opening on one side. 



A. asplenioides : frond bipinnate ; segments lanceolate, incisely ser- 

 rate ; serratures 2 3-toothed ; sori oblong, lunate. 



HAB. Moist woods. %feet high ; frond smooth ; sori at length sub- 

 confluent. 



* * * Involucrum hemispherical, bursting at the top. 



A. punctilobulum : frond bipinnate, oblong ; divisions oblong, pinnati- 

 fid ; segments with the superior margin incisely dentate ; stipe some- 

 what hairy. 



HAB. Shady woods. Frond 18 in. high, thin ; sori minute, neaa 

 tke margin. 



