f 



r 



fi 



ON THE CLASSIFICATION OF FER.NS. 97 



'No scarious scales on the stalk. No glands on the leafy 



part ASPIDIUM THELYPTERIS. 



22 -j Stalk with brown scarious scales at the base. Minute glands 



on the under surface of the segments. 

 L ASPIDIUM OREOPTERIS. 



Segments of the pinnas oblong, very numerous, scarcely 



broader at the base ASPIDIUM FlLlX MAS. 



Segments ovate, wedge-shaped at the base. 



ASPIDIUM CRISTATUM. 



'Segments of the pinnas with finely-pointed, almost prickly 

 teeth ; the inner lobe or tooth at the base much larger 



24 4 than the rest ASPIDIUM ACULEATUM. 



I Segments of the pinnas with shortly-pointed teeth or pin- 

 t. natifid ; the lobes of each side similar 25 



' Sori circular. No indusium POLYPODIUM ALPESTRE. 



Sori circular, with a kidney-shaped or almost peltate indu- 



25 -{ sium attached by a point 26 



I Sori rather oblong, with an indusium attached along one side. 

 ^ ASPLENIUM. 



( Segments ovate or ovate-lanceolate. Indusia conspicuous 



26 I and persistent ASPIDIUM CRISTATUM. 



( Segments oblong-lanceolate 27 



Indusia conspicuous and persistent. 



ASPIDIUM RIGIDUM. 

 Indusia small and often soon disappearing. 



ASPIDIUM SPINULOSUM. 



The way in which this index is used is as follows : 

 Suppose we have the Common Hart's-tongue, Scolo- 

 p&ndrium vulgare, in our hands, we look to the para- 

 graph numbered 1, and here we have three forms of 

 fructification mentioned. The form to which the Sco- 

 lopendrium belongs is " Fructification on the back or 

 under side." Opposite this is the figure 5. This is to 

 direct us to paragraph 5. Here we find two characters 

 of the fronds noted. Our Scolopendrium belongs to 

 the division in which the " fruiting and barren fronds 

 are similar, or nearly so," and opposite this is the 

 number 8. We now turn to paragraph. 8, and here we 



H 



