GENUS VI. 
POLYSTICHUM, Schott. 
SHIELD FEKX. 
GKX. CHAR Sori round, medial. Indusium circular, 
peltate or attached by its centre. Veins free ; midvein 
distinct; venules forked or pinnately forked, the lowest 
anterior one or more fertile. 
This genus embraces a set of British Ferns, the ex- 
tremes of which are of very dissimilar appearance, but 
they are so closely connected by an intermediate series that 
much difference of opinion prevails as to what should be 
regarded as distinct. We have adopted a middle course, and 
believe the arrangement here proposed to be a natural one. 
This group being the most typical portion of the old genus 
Aspidium, it is proposed to retain for it the English name 
of Shield Fern given to that genua, adopting its equivalent 
Buckler Fern for the group of Lastrea. 
The name is derived from the Greek poly many, and 
srtichos order ; in allusion to the numerous regular lines in 
which the sori are disposed. 
1. Polystichum Lonchitis, J?ofA. Rough Alpine 
Shield Fern, or Holly Fern. Fronds linear-lanceolate 
rigid pinnate, pinna; spinose-serrate, auricled at the base 
above and oblique below, not lobed. 
G 2 
