AMERICAN MIDLAND NATURALIST. I9I 
From 1885, another twenty years and somewhat more had 
passed when there was announced *A Flora of Colorado, by 
. A. Rydberg;” this in 1896. Those twenty years covered a 
period of the greatest activity of exploration and research 
into Rocky Mountain botany. Within those two decades more, 
and more effective, work had been done in that field than in 
the hundred years preceeding them. My own contributions 
in California Academy Bulletins, in the five volumes of my 
Pittonia, and in earlier volumes of the journal Erythea, which 
I had established, will be cited henceforward for the greater 
part of this constructive work; and next after my own, both 
in point of time, and the amount of work accomplished, are 
the entensive contributions of Dr. Rydberg, in his “Flora of 
Montana," and in a long list of able studies published largely 
and he can not but have set his hand to the task with some 
enthusiasm ; otherwise he could not have fulfilled it so well. 
This Colorado Flora of Rydberg I cannot help thinking of 
having made possible another book of Rocky Mountain 
botany, which, only three or four years behind it, has lately 
appeared under the title of a “New Manual of Botany of the 
Central Rocky: Mountains." The authorship is divided be- 
tween Professors John M. Coulter and Aven Nelson. It pur- 
ports to be a new edition of the old compilation of 1885, yet 
is said to have been written entirely by my friend the Pro- 
fessor at Laramie, Wyoming; and it is about as different from 
the earlier book as can well be imagined; is even an incom- 
parably more useful book; this notwithstanding that the 
earlier “Manual” was in a manner faultless, while this later 
one is full of faults. 
owever, the only book with which instructively to com- 
pare Professor Nelson's work is not the Rocky Mountain Man- 
ual of twenty years since, but Rydberg's Flora of Colorado, 
named above, and almost as recent. i 
The first of several contrasts that will be noted by one 
acquainted with the whole field will be in respect to the di- 
mensions of the books; for the Rydbergian volume, embracing 
probably less than one-third the geographic area of the Nel- 
sonian, and which ought to have been by much the smaller o 
the two, is manifestly the larger; and this despite the fact that 
in it there are no diagnoses of the genera or species, whereas 
in the other both genera and specis are described, and that 
in no eramped or niggardly manner. But this contrast of di- 
mensions might chance to prove of no great significance. In 
: th, the paper is thinner in the Nelsonian volume, also the 
type used is a trifle smaller. Yet again, the Rydbergian page 
