ag, i" 
> eae 
As 
216 Statistics of the Flora of the Northern States. 
Thus it appears, 1, that, of our 19 extra-Kuropean orders not 
peculiarly American, only 3 or 4 are represented on the western - 
or Pacific side of the United States, while all but one are repre- 
sented in the corresponding parts of Eastern Asia ;—indicating a 
curious analogy in the vegetation of the eastern sides of the two 
great continental masses in the northern hemisphere, which is 
also borne out, though not so strikingly, in a comparison of the 
nera. 
D. That the flora of the Northern United States is remarkably 
rich in ordinal types, as compared with Europe, which, (exclu- 
sive of the Mediterranean region, furnished with two or three), 
has only seven orders that we have not, while we have 26 that 
are wholly unknown to the European flora. 
3. And it is worth noticing that our additional or character- — 
istic orders are all of warm-temperature or sub-tropical general 
character (which is the more remarkable when the lower mean 
temperature of the year as compared with that of Western Ku- 
rope is considered): all of these 26 orders have their principal 
development in the tropical regions, excepting six of the smaller 
ones; and three of these have tropical or sub-tropical repre- 
sentatives, : | 
4, But the peculiar and extra-European families do not pre- 
dominate, nor overcome the general European aspect of our — 
vegetation, on account of the fewness of their species. Of the — 
est in our flora (Hydrophyllacee) we count only 11 species; — 
and the whole 26 orders give us only 64, or barely three per 
cent of our phenogamous species. a 
_ Our Pheenogamous genera, 681 in number, average three spe- 
cies apiece. Far the largest genus is Carex, with 182 species. 
On the other hand one half of our genera are represented by — 
single species; and about 92 of these are monotypic, having only 
a single known species. Mee 
The genera which are strictly confined within the geographical ; 
our extra-Huro henogamous genera are enum 
their respective families, and their distribution in longitude i8 
attempted to be given in the two parallel co - 
