PREFACE. 
TuEsE contributions to the Botany of South America 
are the results of observations made by the Author, during 
several years residence, both on the Western and Eastern 
shores of that vast continent. Having availed himself of the 
opportunity of examining many plants in the living state, 
and also preserved drawings and details of a great number, 
he proposes to select from these, such as may be still undes- 
cribed, or yet imperfectly understood. In the course of 
these investigations, he has met with many ambiguities in 
several already recorded species, and after a careful exa- 
mination of dried specimens, whenever they have been 
within his reach, he has sought to ascertain how far they 
severally correspond with the most authorized generic cha- 
racters, and how far it becomes necessary to remodel these 
characters, in accordance with more recent, and more 
extended observations: in this way, he hopes to have 
collected a few satisfactory materials towards monographs of 
several genera; these will not be offered in any regular 
order, but as the subjects present themselves to his notice. 
In his endeavours to carry out this plan, he has received 
much kind assistance from Sir W. Hooker, and he has great 
pleasure in acknowledging his obligation to that dis- 
tinguished Botanist, for the liberality with which he has 
afforded the use of his valuable library of reference, and the 
