POLYSTICHUM AXGULARE. 



77 



vein. Fructification on the under side of the fi'ond, usually- 

 spread over the upper two thirds. Sori circular and diminutive. 

 Sometimes confluent. Indusium orbicular and membranaceous. 

 Spore cases numerous, and brown in colour. 



The fronds firom two to four feet in length, and brilliantly 

 green. 



There are many varieties of this lovely Fern, now to be 

 described: — 



Fig. 45. 



AcrxuM, WoUaston. (Fig. 45.) — An interesting and distinct 

 variety, in which the pinnules are much auricled, the shape 

 being acute narrowish falcate, distinctly stalked. It has been 

 found growing in Devonshire, Hampshire, and Sussex. My 

 obligations are due to Mr. Wollaston, of Chisselhurst, and 

 Messrs. Stansfield, of Todmorden, for fronds. This Fern 

 approaches the normal form of Polystichum aculeatum. 



BiSERRATUM, Moore. (Fig. 46.) — An Aculeatum-lookm^ Fern, 

 mostly having an exceedingly lengthy stipes. It is of a lax 

 habit. The outline of the pinnules nearly resemble those of 

 the variety Intermedium of A\ ollaston. The pinnules are large 

 and broad and inciso-serrate ; all but the anterior lobe biserrate 

 and aristate. A common form in Jersey. As its name implies, 



