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Genus V. POLYSTICHUM, Both. 



THE Polystichums form a small and very distinct group of 

 evergreen Ferns, some forms of which rank among the most 

 beautiful of our native species. They once formed part of 

 the genus Aspidium, the token of admission to which, was 

 the presence of round seed-patches covered by a scale. 

 From the allied genus Lastrea, the PolysticJiums are known 

 by their having the scale-like cover of the sori circular, 

 without a lateral notch, its attachment being by a little 

 stalk in the centre : this form is called peltate. To a prac- 

 tised eye they are also known by a more rigid texture, and 

 by having altogether a more spiny appearance than even the 

 spinulose species of Lastrea ; but these means of recognition 

 the novice can turn to but little account. The alpine form 

 of the genus is strictly evergreen, and the others acquire this 

 character when in a sheltered situation, but if they are much 

 exposed, the fronds will be killed by a sharp frost. In 

 general, however, they retain their fronds without much dis- 

 figurement from frost, quite through the autumnal quarter, 

 and often far into winter. The British species of Pofysti- 

 chum are three in number. 



The name Polystichum is compounded of two Greek 



