KEY TO THE GENERA. 311 



KEY TO THE GRAPE FERNS. 

 (Botrychium^ 



PAGE. 



Plant large, fruiting in spring, sterile portion much divided 



B. Virginianum. 42 

 Plant smaller. ....... 



Fruiting in autumn, sterile portion long stalked, triangular 



B. obliquum. 54 

 Fruiting in summer . . . 



Plant very fleshy, sterile portion with mostly lunate seg- 

 ments. . . . . . B. Lunar ia. 51 



Plant less fleshy. ...... 



Sterile portion short stalked, above the middle of the 

 stem. . . . B. matricaricefolium. 60 



Sterile portion stalked usually below the middle of the 

 stem. . . . . . B, 'simplex. 58 



Sterile portion sessile near the top of the stem 



B. lanceolatum. 59 



KEY TO THE WOOD FERNS. 

 (Aspidium^) 



Fronds pinnate, the pinnae pinnatifid. 

 Blade thin, deciduous. 



Lower pinnae reduced to mere lobes 



A. Noveboracense. 120 

 Lower pinnae not or little reduced. 



Veins simple . . A. simulatum. 123 



Veins forked . . A. Thelypteris. 117 



Blade rather thick, evergreen. 



Fronds small, narrow, rock species A.fragrans. 147 



Fronds large, two or more feet high. 



Lower pinnae, nearly triangular A. crtstatum. 139 

 Lower pinnae longer. 



Sori close to the margin. A. marginale. 135 



Sori nearer the midvein. 



Frond lanceolate . A.filtx-mas. 136 



Frond ovate . A. Goldieanum. 137 



Fronds twice pinnate with lower pinnules pinnatifid. A, Boottit. 141 



Fronds nearly thrice pinnate . . A. sptnulosum. 143 



