PREFACE. 
wherefore that long doubted native of Britain must 
again remain. at least a doubtful British species. 
But here, the author, yet with diffidence, inclines 
to disagree with his coadjutor; simply because the 
Hessleton Gill plant is not by any:means the same 
as the common foreign A. umbrosa of our gardens, 
but a very strong variety of it, with much shorter 
petioles and smaller. panicles ; which do not. ap- 
pear to alter under the tests of cultivation. This 
variety, Mr. B. supposes, may be the same as the 
Rolertsonia umbrosa, which is found on the banks 
of the Clyde, although in all probability not of 
spontaneous origin. And a plant Mr. B. received 
from the Edinburgh Botanic Garden (and which 
he coujectures is the Clyde one) under the.name 
of Saxifraga umbrosa, ** is so much like the Hes- 
sleton Gill one, that it might well pass for it." 
Such, in a letter, are his words ; and-he also says 
that he saw R. umbrosa ** almost naturalized" in 
"a romantic spot near:a gentleman's seat in the 
county of Wicklow 
- With respect to the wliole tribe bf. Hypnoidéan 
Saxifrages, Mr. Bree is inclined to think that they 
are really as sportive on the Welch. and Seotch 
mountains, as that of Roberiscaia on the moun- 
tains of Ireland. And this opinion he takes up not 
rashly, but from having actually observed similar 
"variations, and innumerable gradatious in hue, and 
size ; and even, as he imagines, in the laciniation 
of their leaves. | Wherefore, it has been deemed 
proper in the present Essay to reduce the number 
of supposed £ypnoidéan species, as well as those 
XV 
