LASTllEA. 107 



under the name of LopJiodmm, a perfectly unnecessary 

 and characterless group. 



Lastrea cristata, Prcsl. 



Crested Pridijj-toothed Buckler Fern. (Plate VI. fig. 2.) 



This is the simplest of the British forms of a group of 

 species intimately related to each other, and formerly 

 known as the Crested Shield Ferns. This group consists 

 of the plants to which the several names of L. cristata, 

 id'ujlnosa, splnidosa, dilatata, and wmida, have been 

 given ; and they form a series so closely connected, that 

 some very eminent botanists consider them as all belong- 

 ing to two species only, cristatct and dilatata, the other 

 forms being regarded as mere varieties. This view of the 

 subject is, we believe, almost exclusively confined to those 

 •whose lot it has been to study the Ferns in a general way, 

 and mainly from a large suite of herbarium specimens. 

 The magnitude of the subject, in such a form, necessarily 

 leads to generalizations, and the acknowledgment only of 

 the most obvious differences. Those, on the other hand, 

 who study a smaller series, confined to certain geographical 

 limits — our own country, for example — being unperplexed 

 by the magnitude of their subject, are content to admit 



