11)2 HISTORY OF BRITISH FERNS. 



in the form of an urn or vase, and within them bearing the 

 fructification. 



The fronds are pendulous, and vary from an angular- 

 ovate to a lanceolate form, the divisions being considerably 

 undulated, so that they acquire a crisped appearance. The 

 first series of lobes are usually of an ovate-lanceolate form ; 

 the next series shorter, more ovate, and the third series of 

 divisions narrow, more or less linear. The ultimate 

 branches of the veins which extend into the divisions of 

 this third series, end just at or within the apex of the 

 lobes if they are barren ; but if they are fertile, they are 

 produced beyond the margin, and surrounded at the base 

 by the urn-shaped involucre, within which the spore-cases 

 are placed. Sometimes the involucre is so placed as to 

 appear immersed within the margin, but it more frequently 

 projects beyond the margin. There is also considerable 

 variation as to the length to which the bristle-like recep- 

 tacle is extended beyond the involucre ; sometimes scarcely 

 exceeding it in length, and sometimes being four or five 

 times as long. 



The variety Andrewsii, is the lanceolate form of this 

 plant, in which the pinnae or first set of divisions are 

 narrow and distant ; it is tolerably distinct from the 



