320 CONTRIBUTIONS TO 
America, the results of the observations made by him 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 
preserved drawings and details of a great number, he proposes 
to select from these such as may be still undescribed or yet 
imperfectly understood. Whenever the subject admits, he 
will collect all the materials he can command towards mono- 
graphs of each genus, not in any regular order, but as the 
subjects present themselves. In his endeavours to carry out 
this plan, he has received much kind assistance from Sir 
William Hooker, and he has great pleasure in acknowledging 
his obligation to that distinguished Botanist for the liberality 
with which he has afforded the use of his valuable library of 
reference and the freest access to his extensive herbarium, 
which is particularly rich in the botanical productions of 
South America. From this fertile source, and the different 
herbaria in the British Museum, as well from the materials 
in his own collection, he has prepared the following contribu- 
tions, which he proposes to follow up by illustrations drawn by 
himself, exhibiting the details, which according to his views, 
tend to exemplify the characters of each genus referred to.* 
The vast accumulation of plants during the last few years - 
collected in all parts of the globe, has been so great, that it 
becomes absolutely necessary to define with greater accuracy 
the limits, not only of genera, but of species, and where this 
can be accomplished upon sufficient evidence, much will be 
done towards removing the confusion that exists in so many 
cases; but even should the author of these contributions 
succeed in only a few instances, he hopes to render some 
service, though it be not very great, towards the advancement - 
of the science of botany. 
* This work will afterwards appear with the addition of plates in a 4to- 
form under the title of “ Illustrations of South American Plants, &e.” Y» 
the following Contributions, reference in foot notes will be made to the 
plates illustrative of such subjects in the work alluded to. 
