WASHmaxoNj D. 0., 31ay 10, 1874. 



Sill : I have the honor to transmit herewith my report on the botan- 

 ical results of the field-season of 1873 in Central Colorado. The party 

 of your command under which this collection was made was in charge 

 of Lieut. Wm. L. Marshall, Corps of Engineers. The i)lants collected 

 in j^rizbna and New Mexico will be enumerated and commented upon 

 at the close of the present season. « 



It could hardly be expected that the Colorado collection should con- 

 tain many new species, as the ground had been already so thoroughly 

 botanized over by Parry, Hall, Harbour, Yasey, Porter, Canby, and 

 others. The collectiouj however, is large and valuable, and not entirely 

 devoid of novelties. 



The names of several of our most eminent botanists appear over the 

 orderSj the representatives of which they have been kind enough to 

 name ; but besides this, I have received valued assistance from the 

 same gentlemen, of such a character that I could not well specifically 

 allude to it at each instance, and I would here state that especial thanks 

 are due to Prof. Asa Gray, Mr. Sereuo Watson, Prof. D. 0. Eaton, Mr. 

 Thomas P. James, Dr. George Yasey, Dr. George Thurber, and Mr. Jo- 

 siah Hoopes, for their generous aid. 



I have elsewhere alluded to the activity of Professor Wolf in the 

 labor of collecting. 



It is also a pleasant duty to say that, but for the interest manifested 



by Lieut. Wm. L. Marshall in the work, so fine a collection could not 



have been made. , 



I have the honor to be, respectfully, your obedient servant, 



Geo. M. Wheeler, 



J. T. EOTHROCK, 



Acting Assistant Surgeon^ U. S. A. 



First Lieutenant Corps of Engineers^ 



