THE SOFT PRICKLY SHIELD FERN.* 



PolysticJium angulare. PEESI. 



This specimen is not easily distinguished from 

 P. aculeatum, though certainly distinct. The two 

 may, however, be generally known from each other by 

 the following differences : 1 P. angulare is less 

 stout, less erect, and altogether less rigid in texture, 

 normally lax and more herbaceous, while equally large 

 or larger. 2 jP. aculeatum has its pinnules either 

 confluent or decurrent (in which case there is no diffi- 

 culty in distinguishing it), or when the pinnules are 

 distinct, as in the most perfect plants, they are wedge- 

 shaped at the base, the anterior side being truncate, 

 and the posterior obliquely incised in straight lines, the 

 two lines describing an acute angle, by the apex of 

 which they are attached to the rachis ; while in P. 

 angulare the truncated anterior base is more curved in 

 outline and the two lines of the base describe a right 

 angle or an obtuse angle, at the apex of which is a dis- 

 tinct slender stalk, by which they are attached. 3 

 P. aculeatum has its sori attached at a point along 

 the middle part of the venule, the apex of which is 

 carried out to the margin of the pinnule, the sori thus 

 being placed nearer to the point of forking or branching 

 than to the apex of the venule; while in P. angu- 



* Or Angular-lobed. Polystichum aculeatum, Aspidium angu- 

 lare, A. aculeatum, Polypodium angulare, &c. 



