952 ESSAYS. 
dor, to which was added a couple of hundred of species known 
to him outside these limits northwestward. 
Torrey and Gray’s Flora took the initiative in annexing 
Texas, ten years before its political incorporation into the 
Union ; although the only plants we then possessed from it 
were certain portions of Drummond’s collections. California 
was also annexed at the same time, on account of Douglas’s 
collections, and those of Nuttall, who had just returned from 
his visit to the western coast, which he reached by a tedious 
journey across the continent over ground in good part new to 
the botanist. Douglas had already made remarkably full 
collections along a more northern line. The British arctie 
explorers, both by sea and land, had well developed the bot- 
any of the boreal regions, and Sir William Hooker was bring- 
ing out the results in his Flora of British America. Of 
course our knowledge of the whole interior and western re- 
gion was small indeed, compared with the present; and the 
botany of a vast region from the western part of Texas to the 
Californian coast was absolutely unknown, and so remained 
until after the publication of the Flora was suspended. 
As to the number of species which Torrey and Gray had to 
deal with, I can only say that a rapid count gives us for the 
first volume about 2200 Polypetale ; that there are one hun- 
dred and nine species in the small orders which in the second 
volume precede the Composite ; and that there are of the 
Composite 1054. So one may fairly conclude that if the 
work had been pushed on to completion, say in the year 1850, 
the 3076 species of Pursh’s Flora in the year 1814 might have 
been just about doubled. Probably more rather than less ; for 
if we reckon from the number of the Composite, and on the 
estimate that they constitute one-eighth of the phaenogamous 
plants of North America, instead of 6150, there would have 
been 8430 species known in the year specified. 
It most concerns us to know the number of species which, 
after the lapse of thirty years more — years in which explora- 
tion has been active, and has left no considerable part of our 
great area wholly unvisited — the now revived Flora has to 
deal with. We can make an estimate which cannot be far 
