xn 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- 



