224 VARIETIES OF FERNS IN THE BRISTOL DISTRICT. 



are gonorally their tendency to a soft and papery texture, a 

 light yellowish colour, and barrenness— especially the latter. 

 It is this that causes the extraordinary beauty in Tar- 

 leyense ; — being barren, the pinnule does not fold over to 

 form an indusium for the sori, and the strength which 

 would, in the ordinary course, be expended in the produc- 

 tion of the sori and spores, exhausts itself in additional 

 luxuriance, this foliose character being generally one of the 

 peculiarities of this class. 



By way of illustration of the other marked na,tural cha- 

 racters, let us take Polystichum angulare, one of the four 

 species in which alone all the marked characters have as yet 

 been known to appear ; the one m which, on the whole, these 

 characters have appeared in the greatest variety (its only 

 possible rival in this respect being Athyrium f.-foomina), 

 and undeniably the one in which, with the exception per- 

 haps of the cruciate class, they have been developed to the 

 greatest perfection. The natural deviation of P. angulare, 

 indeed, has been such as to render necessary a more com- 

 plex classification. This, no doubt, is mainly to be attri- 

 buted to P. angulare being a stipitato, or rather per-stipitate 

 fern, the stipitate character being preserved to its minutest 

 divisions, even to the third division of the lobe or pinnule. 

 This brings us to the next or the Divided and Decomposito 

 Class, which (leaving out the plumose forms, which are 

 also divided) includes the forms with divided lobes or 

 pinnules, a class disputing with the plumose the distinction 

 of producing the most beautiful of the varieties of Britisli 

 ferns. The well known proliferous form of angulare, of 

 which so many improved varieties have since been found 

 and raised, is a specimen of this class. 



The Imbricate and Crispate class speaks for itself. These 

 forms are never beyond medium size and are generally more 



