ESSAYS. 
EUROPEAN HERBARIA.? 
THE vegetable productions of North America, in common 
with those of most other parts of the world, have generally 
been first described by European botanists, either from the 
collections of travelers, or from specimens communicated by 
residents of the country, who, induced by an enlightened curi- 
osity, the love of flowers, or in some instances by no inconsid 
erable scientific acquirements, have thus sought to contribute, 
according to their opportunities, to the promotion of botanical 
knowledge. From the increase in the number of known 
plants, it very frequently happens that the brief descriptions, 
and even the figures, of older authors are found quite insuffi- 
cient for the satisfactory determination of the particular spe- 
cies they had in view ; and hence it becomes necessary to refer 
to the herbaria where the original specimens were preserved. 
In this respect, the collections of the early authors possess an 
importance far exceeding their intrinsic value, since they are 
seldom large, and the specimens often imperfect. 
With the introduction of the Linnzan nomenclature, a rule 
absolutely essential to the perpetuation of its advantages was 
also established, namely, that the name under which a genus 
or species is first published shall be retained, except in certain 
cases of obvious and paramount necessity. An accurate de- 
termination of the Linnzan species is therefore of the first 
importance ; and this, in numerous instances, is only attained 
with certainty by the inspection of the herbaria of Linnzus 
and those authors upon whose descriptive phrases or figures 
1 American Journal of Science and Arts, xl.1. (1841.) 
