Xll 
INTRODUCTION. 
and the publications of Professors T. S. Brandegee, Aven Nelson 
and M. E. Jones, Mr. G. E. Osterhout and Miss Alice Eastwood in 
the Botanical Gazette, Bulletin of the Torrey Botanical Club, Zoe, 
Erythea and the Proceedings of the California Academy of Sciences. 
The author has tried to verify the records referring to Colorado 
plants given in these publications. Some of these records have 
been proven erroneous. In some cases the specimens were wrongly 
determined, in others the stations at which they were collcted are 
not within the present boundaries of the state of Colorado. Of 
course, all such species have been excluded from this catalogue. 
The author has also excluded a few more, which he thought should 
be included in the same category, although he has not been able to 
prove them erroneously referred to the flora of Colorado, as for 
instance Californian, Mexican, or Alleghanian species, accredited 
to Colorado but not to the intervening states. He has also been 
forced by circumstances to exclude a score or so species recently 
described from Colorado, but wholly unknown to the author. Not 
being able to include them in his “ keys ” and being uncertain 
whether the descriptions really characterize new and valid species or 
merely represent redescriptions of old ones, he thought it best to 
leave them out until more information could be had. 
At first it was suggested that a catalogue should be prepared 
similar to the author’s Catalogue of the Flora of Montana and the 
Yellowstone National Park. After some consultation with Professor 
Carpenter, it was agreed that the publication would be of more value 
to the plant lovers of Colorado, if some characterization of the 
plants could be given. A descriptive botany or so-called manual 
was out of question. The author would not have time to prepare 
such a one within a reasonable time and the College did not have 
funds available to pay for the cost of preparing it. The author 
had already begun the work on a botany of the whole Rocky 
Mountain region. He was preparing the “ keys ” first, leaving the 
main descriptive work to be done later. Some of these keys were 
already made, and he hoped to have most of them ready by the 
time the catalogue was ready to go to print. It would not take 
much more work to abstract from these keys the parts referring 
to the Colorado genera and species, than to cite a number of refer¬ 
ences to descriptions as was done in the Flora of Montana and the 
Yellowstone National Park. The author showed Professor Carpen¬ 
ter a catalogue prepared in this way, viz., Dr. T. C. Porter’s Flora 
of Pennsylvania. This was taken as a model, except that the locali- 
