810 THE AGE OF SOME EXISTING SPECIES OF PLANTS, 
would be of no value. The short, vague, and insufficient descrip- 
tions a the still earlier botanists cannot even be taken into con- 
sidera 
“rae precision might be expected from gp illustrations that 
have been in use in botanical literature from the earlie st time es; 
fictitious. The careful and minutely exact illustrations which are 
to be found in many modern systematic works are too recent to 
supply materials for = pirad any changes that may have taken 
place in the elements of a flor 
ut the means of comparison which we look for in vain in the 
published literature of science may be found in the collections of 
dried plants which botanists have formed for several generations. 
The local herbaria of sce a day represent or; only the different 
species found in a cou but the various slg which occur 
together with their distribation. They must supply the most 
certain materials for the minute comparison at any future epoch of 
the then existing vegetation with that of our own d 
to believe, o the practice of making herbaria. Ghint’ 
pupils, Reeder and peelnnas, formed extensive collections. 
Caspar Bauhin, whose ‘ Prodromus’ was the first attempt to digest 
the literature of botany , left a mae deat herbarium, still pre- 
served at Basle. No collection of English ponte: a ~— to exist 
older than the middle of the seventeenth century; a volume 
containing some British and many exotic Sie mlieeels in the 
year 1647 was some y 8 ago acquired by the British Museum. 
Towards the end of that century great activity was manifested in 
y 
e, which were ae a by ‘hs. country in 1759 when the 
museum of Sir Hans Sloane became the nucleus of the now 
extensive collections of the British Museum. The most ee 
of these collections in regard to British plants is a herbarium of 
Adam Buddle, collected nearly two hundred years ago, ia con 
ae i an extensive series, which formed the basis of a British 
