60 HOW TO KNOW THE FERNS 



the other pinnules. The pinnules are provided 

 with sharp teeth, and it should be noted that 

 they have nothing very decided in the way of 

 stalks. Actually they are what botanists call 

 decurrent that is, tending to run together at 

 the base. In some varieties of this species the 

 tendency is more marked than in others. 



The sori are placed on either side of the mid- 

 veins of the pinnules, and these are usually con- 

 fined to about half the upper portion of the back 

 of the frond. 



The Hard Prickly Shield Fern is very widely 

 distributed in England, and it is to be looked for 

 in shady woods. It is an exceedingly easy plant 

 to grow, and thrives even in town gardens. The 

 plant is evergreen in habit. 



Polystichum (Aspidium) angular e. It is not 

 regarded by some botanists as an established 

 species, but is thought to be a variety of A. 

 aculeatum. However, there are certain differ- 

 ences which appear to be specific. The Soft 

 Prickly Shield Fern. 



As in the Hard Prickly Shield Fern, we find a 

 tufted root-stock from which grow lanceolate 

 fronds. We notice the same short stipes and 

 the narrow pinnae on the leafy portion tapering 

 to a point. In this species it is said that the 

 pinnules at the base are more nearly equal in 

 size than is the case with A. aculeatum. The 

 pinnules are also more definitely stalked in the 

 former than in the latter. In the case of the 

 Soft Prickly Shield Fern, it is noticeable that all 

 parts of the stalk of the frond both stipes and 

 rachis, and even the rachides are covered with 

 brown scales. It is said, too, that the droop 

 of the fronds is more pronounced in the Soft 

 Prickly Shield Fern than in the Hard Prickly 

 Shield Fern. 



