LASTREA. 117 



species intimately related to each other, and which are some- 

 times in the aggregate called Crested Perns; the latter 

 name is, however, more usually applied only to L. cristata, 

 of which we have used it as the equivalent. The group 

 alluded to consists of L. cristata, uliginosa, spinulosa,dilatata 

 in its many forms, and fcenisecii or recurva, plants whicli 

 form a closely connected series, so close, indeed, that some 

 very eminent botanists consider them as all belonging to 

 two^species only, cristata and dilatata, the other forms being 

 considered as mere varieties. This view of the subject is, we 

 believe, almost exclusively confined to those whose lot it has 

 been to study the Terns in a general way ; and the magnitude 

 of the subject in such a form necessarily leads to generaliza- 

 tions, and the acknowledgment only of such differences as are 

 the most obvious. It is, in fact, often inconvenient for the 

 general botanist to search after or take cognizance of very 

 minute 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, as necessarily search for and 

 find differences of another kind, less obvious at the first 

 glance, but to be found if looked for ; and these, when 

 proved to be constant and unvarying, are relied on as proper 



