282 Notice of a Flora of North America. 
nists who have had the courage to attempt for themselves the 
study of this vast and most intricate genus, and its congener Soli- 
dago. We entirely approve of the reduction of many doubtful 
species to mere varieties of a recognized type ; and it appears that 
in many cases the approximation of forms wastoo close to admit 
even of this distinction: thus, under A, levis, Linn., we have 
nine synonyms! whilst only two marked varieties of the plant 
occurred to the authors, who say, “'The large suite of specimens 
before us have been named for the most part by several distin- 
guished botanists, whose determinations so seldom accord, te 
we feel the greater confidence in our own opinion.” * *— 
Now, we are very far from feeling any surprise that these. = 
tinguished botanists should not have understood each other in 
such cases, as indeed their laborious volumes sufficiently prove; 
and we should have esteemed it very marvellous had it been 
otherwise. A variety (perhaps in the first instance accidental) 
is introduced into some one of the botanical gardens of Europe, 
where it is carefully propagated by division of the root, and in 
time distributed generally amongst them. It is not difficult to 
perceive, that such characters as it originally presented are thus 
perpetuated throughout the series, and the peculiarity of form 
becomes known, whilst the slight modification of the origi 
type, from which, 4 was derived, is not susceptible of precise 
definition in terms. Indeed, it may be said, that the characters 
relied upon for the discrimination of even ” acknowledged and 
understood species, are but modifications, more or less marked, 
of the same general structure, and hence the many difficulties 
which t have wheel and the perplexed and egiigy te sn 
