872 



Centaurea nigrescens {Willd.) is adopted for a species distinct 

 from C. nigra, and from a variety " radiata" of C. nigra. Centaurea 

 Jacea (Z.) is retained as a British species, also, but the author inti- 

 mates that he has himself seen no native specimens. This appears 

 remarkable enough, seeing that his friend Mr. Borrer is the authority- 

 cited for the occurrence of C. Jacea in Sussex. Angus and Belfast 

 are the two other localities indicated ; and it would thus appear that 

 the C. Jacea occurs in England, Scotland, and Ireland. Is not the 

 plant so called just the same thing as our author's C. nigrescens, 

 plentiful in some of the most southern counties of England ? 



Thrincia hirta affords an example of the author's resolute ad- 

 herence to a bad (because very inconstant) character, after its 

 inconstancy has been strongly and explicitly pointed out. The words 

 " involucre glabrous " are reprinted from the former edition, in the 

 specific character of T. hirta. This inaccuracy becomes the more 

 likely to mislead, because the variety " dubia" of the former edition, 

 distinguished by having its "involucral scales hairy," is now sup- 

 pressed, although formerly alleged to be "probably a distinct species." 

 It is curious to find varieties deemed not worth mentioning in 1847, 

 although four years before they had been thought " probably distinct 

 species." We hail these changes as so many indications that the 

 author's taste for species-making has been checked by the freely ex- 

 pressed comments upon that trouble-creating practice. However, the 

 avowed existence of such a variety is sufficient to prove the author's 

 knowledge that the character of " involucre glabrous " was unsound 

 for specific diagnosis; and instances of hairy or hispid involucres are 

 so frequent that any botanist may find them. Why is the inaccurate 

 character reprinted ? We can scarcely suppose it to have been done 

 in a spirit of petulant opposition against a critic of the former edition, 

 w^ho questioned the alleged probable distinctness of the variety ' du- 

 bia,' because "the involucrum varies in all degrees from glabrous to 

 very hairy." And yet this, in connexion with other similar reiterations 

 of errors, almost justifies such an answer to the query. 



In the troublesome genus Hieracium, the species of which are yet 

 so imperfectly ascertained and agreed upon, wide differences of opinion 

 may be expected to prevail, not only between different botanists, but 

 even with the same botanist at different times. The two editions of 

 the Manual are illustrations of the latter ; changed names and changed 

 views of species occur to an extent which Vestigians might hail as an 

 indirect evidence that perfectly definite species have no existence out 

 of books, or in them either. H. nigrescens ( Willd.) is now adopted 



