for the advance of Botany. 119 
prove, what we have frequently endeavoured to enforce by exam- 
ples throughout the present volume, that no precise shape of leaf or 
quantity of pubescence is of any value, although both of these seem 
in each species to be limited within certain variations. With re- 
gard to varieties, we have seldom distinguished any, unless well 
marked and tolerably constant; we are. aware, indeed, that these 
correspond to what some naturalists call species, but our own ob- 
servations have convinced us, that varieties and forms, as well as 
species, may be constant in similar situations, and even in widely 
different situations, for many years, if raised from seeds either ob- 
tained from the original locality or from cultivated plants ; the cul- 
tivated cerealia and garden vegetables ought to lead to such an hy- 
pothesis without any additional proof." 
The extent to which uncertainty prevails on this question, cannot 
be better shewn than by the remarks of Dr Lindley, in the new edi- 
tion of his Synopsis of the British Flora.* Here we find this dis- 
tinguished botanist, who has devoted so much attention to the two 
genera Rosa and Rubus, confessinghimself incapable of deciding whe- 
ther certain forms in the latter genus constitute one, three, or four- 
teen species. " When I first began to attend to this very difficult 
subject, I could not avoid remarking that the same distinctions and 
peculiarities which had led to the establishment of many of these 
(species), would also separate many other forms of the genus ; and 
it appeared to me that, to be consistent, we ought either to reduce 
the whole to Rubus suberectus,fruticosus, corylifolius, and ccesius, or 
to distinguish a considerable additional number of such species as 
Smith, by the advice of his correspondents who had specially occu- 
pied themselves with the subject of British plants, had been indu- 
ced to admit." " I accordingly advanced the number to twenty- 
three ; certainly not from any expectation that such species were 
either genuine, or likely to prove permanent, but with a view of fol- 
lowing out the recognized principles of distinction, and showing whi- 
ther they must inevitably lead."" It has led me to reconsider the 
subject very carefully, and to examine with more attention the na- 
ture of the principles upon which the modern and recognized spe- 
cies of Rubus have been established ; I have also had six years of ad- 
ditional experience ; and I am bound to declare, that I can come to 
no other conclusion than that with which I have first started, name- 
ly, that we have to choose between considering the four first named 
plants the only genuine British species, or adopting, in a great mea- 
sure, the characters of the learned German botanists, (Weihe and 
Nees von Esenbeck,) who have so much distinguished themselves 
* P. 91. 
