BOTANICAL GAZETTE. 
132 
The area which Pursh’s Flora covered was, ,we may say, the 
United States east of the Mississippi, with Canada to Labrador, to 
which was added a couple of hundred of species known to him out- 
side 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 ot 
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 arctic explorers, both by sea and land, had well developed 
the botany of the boreal regions, and Sir Wm. Hooker Was bring- 
ing out the results in his Flora of British America. Of course our 
knowledge of the whole interior and western region 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 counf gives us for the first 
volume about 2200 Polypet al$; that there are 109 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 con- 
clude that if the work had been pushed on to completion, say in 
the year 1850, the 8076 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 exploration 
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 wrong. In the 
year 1878, my colleague, Mr. Watson, finished and published his 
Bibliographical Index to the Polypetalae of North America, cover- 
ing, that is, the same ground as the first volume of Torrey and 
and Gray’s Flora, completed in 1840. In it the 2200 species of the 
latter date are increased to 3038. The “ Gamopetalce after Com- 
posite e” in the Synoptical Flora, brought out in the same year, 
contains 1656 species. The two together must make up half ot 
our phaenogamous botany, that is, adding the increase of the last 
four years, about 5000 species. And so Mr. Watson adopts the 
estimate of 10,000 species for our known* Phaenogams and Ferns. 
