THE COMMON PEICKLY SHIELD FERN. 



Polystichum aculeatum.* ROTH. 



The Common Prickly Shield Fern is one of the 

 larger and hardier ferns, preferring, however, a loamy 

 soil and the partial shade of woods or hedge-banks, 

 where it grows to the height of from a foot to two feet 

 or more, with a short stipes densely enveloped in rust- 

 coloured membranous pointed scales. The fronds, from 

 four to seven inches across, are, like the Alpine Shield 

 Fern, rigid and leathery in texture, of a shining dark 

 green above, paler beneath, erect and spreading, or 

 occasionally drooping, growing up in a circle in April 

 or May, from a stout tufted stem, or crown. The 

 general typical form is broadly lanceolate ; but the 

 variety LOBATUH is very narrowly lanceolate ; bi-pin- 

 nate, with alternate pinna3, these pinnse being again 

 more or less divided into a series of pinnules, either 

 decurrent that is insensibly merging in the sub- 

 stance of the rachis which supports them, or tapering 

 to a wedge-shaped base and attached to the rachis 

 by the point. The pinnules are of a long crescent 

 shape, with the upper base extended into a small 

 auricle, or enlarged lobe, and the lower base sloped 

 away, the apex going off to an acute point, and the 

 margin notched with spiny teeth. Venation, fructifi- 

 cation, and indusitun, similar to P. LoncJiitis. 



* Poli/podium aculeatum, Linnaeus. Also Aspidlum aculeatum. 



