THE SHIELD (AND BUCKLER) 
FERNS. 
THE ALPINE SHIELD FERN, 
or Holly Fern. 
Polystichum Lonchitis .* — Roth. 
Polystichum is an extensive genus of the group of 
Aspidiese; and consists for the most part of harsh 
spiny evergreen ferns, scattered from the torrid to 
the frigid zone, — but represented in this country by 
only three species : — Polystichum Lonchitis, Poly- 
stichum aculeatum, and Polystichum angular e. These 
species, however, are very variable, and so closely 
connected by intermediate forms that it is difficult 
sometimes to distinguish their exact limits. 
The Alpine Shield Fern is one of the rarer ferns, 
taking its other name of Holly Fern from its hard 
and prickly appearance. It is an evergreen, with a 
scaly tufted stem from the crown of which the young 
fronds are produced in spring, to remain fresh and 
vigorous until the spring following, arriving at matu- 
* The Polyp odium Lonchitis of Linnaeus. 
