POLTSTICHUM. 
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is divided ; and the spore-cases are borne along these 
branches of the veins. The lines of sori on the pinnules 
often become united into a mass, after they have been 
some time developed, especially in parts where they are 
rather crowded. 
Though a minute species, this Fern is widely scattered 
over the face of the globe ; it is plentiful in many parts 
of the south of Europe, and extends as far northwards as 
J ersey. 
It grows readily, as an annual or biennial, sown on 
sandy loam, and kept in a rather warm damp situation. 
Genus IV. POLYSTICHUM, or SHIELD EEBH. 
The group of Ferns formerly called Aspidium, or Shield 
Fern, is now commonly divided into several lesser groups, 
forming the modern genera. The English species of this 
group are now classed under three genera, bearing the 
names of Polystichum, Lastrea^ and Cystopteris. 
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, along 
