148 KEY TO THE GENERA OF FERNS 



Fruit-dots irregularly scattered on the netted veins ; those 

 nearest the midrib sitigle, the outer ones often in pairs which 

 are sometimesyo/«^</ at the ends, thus forming crooked lines. 

 Fronds entire, tapering to a long, slender point. 



Caniptosoriis, p. 4. 



ft t Fruit-dots ro7ind or roiindish, borne on the back 

 or rarely at the end of the veins. Indusium of various 

 forms. 



Indusium circular or roitnd-kidney-shaped, and fixed either 

 centrally or by the sinus, opening all around the margin. 

 Fronds variously divided, and in several species evergreen. 



Aspidium, p. II. 



Indusium inflated or hood-shaped, delicate, and attached 

 by a broad base partly under the fruit-dot on the inner side. 

 It is early reflexed and withered. Fronds in one species very 

 long and narrow, producing bulblets on the under side of 

 rachis. Cystopteris, p. 67. 



Indusium jA7r-j-/5(7/t'i/, fixed under the fruit-dots and either 

 open, or early cleft into ragged lobes or slender inflexed fila- 

 ments. It is inconspicuous in most species. Fronds small, 

 rock -loving. Woodsia, p. 84. 



Indusium cnp-shaped, membranous, open at the top, and 

 attached by its outer edge to a reflexed toothlet which forms 

 one side of it. Fronds large, delicate, tapering and finely 

 divided. Dicksonia, p. 63. 



Without indusium. 



■f Fruit-dots round. 



Fruit-dots large, in a row each side of the midvein, mid- 

 way between it and the margin. Fronds small, evergreen. 



Polypodiiim, p. 3, 



