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XII. — A Monograph of the Genus Pyrola. 
By Mr David Don, Librarian of the Linnean Society j 
M.W.S. 
(Read ^st April 1821,) 
When we contemplate the great increase of new spe- 
cies which Botany is daily acquiring, Monographs are ren- 
dered indispensably necessary to the exact knowledge of 
the species which compose particular genera, and more 
especially of such whose species are nearly related to each 
other. The genus Pyrola^ although far from being nu- 
merous in species, has nevertheless been hitherto involved 
in much confusion. I have corrected the synonymes, and 
endeavoured to improve the specific characters of the older 
species ; but, considering the great difficulty which attends 
such a task, I fear, in the latter point, I have not in many 
instances been successful. For the new or rare species con- 
tained in the following pages, I am indebted to the kind- 
ness of Mr Lambert, and Mr Brown. The last distin- 
guished botanist, who is now in possession of the Banksian 
Herbarium, has with great liberality permitted me to ex> 
