APRIL. 



103 



of their extremities, one being produced by each, variable in length in 

 different kinds, but when quite young becoming laterally confluent int 

 a broadly linear mass, which 

 occupies continuously a position 

 near the edge of the frond, the 

 spuriously indusiate margin being 

 more or less inflected over its 

 outer edge. The group consists 

 of four genera, in all of which the 

 veins are free, so that the manner 

 of division in the fertile fronds 

 furnishes the most obvious dis- 

 tinctions. They are : — Platy- 

 loma, in which the fertile fronds 

 are not materially narrowed ; Pla- 

 giogyria, in which they are much 

 contracted, like those of Lomaria, 

 the fertile divisions (pinnse), 

 linear ; Llavea, in which the 

 fertile fronds are tripinnate, the 



divisions (pinnules) siliquiform, Ji6. Gymnoqrammeje : (a) Gymnogramma rufa. 



that is linear and podlike ; and (6) Grammitis totta - 



Cryptogramma, in which the divisions (pinnules) of the tripinnate fertile 

 fronds are siliculiform, that is ovate, podlike. This latter genus differs 

 only in degree from Allosorus which is placed next it as the first 

 genus in the following series. 



glT. Platylomk^e : Platyloma Brownii. 



In the remaining group (3) the sori are normally punctiform, i. e., 

 consisting of roundish dot-like clusters of spore-cases. This is their 

 typical character. Occasionally the dots become a little elongated, 

 forming a short oblong mass, and these instances doubtless indicate an 

 affinity with Grammitis in the section Gymnogrammece, but they are 

 not of common occurrence. Still more rarely the dot-like clusters 

 placed in a single row between pinnate veins have a tendency to 

 coalesce more or less completely into a line ; this particularly happens 



