PKELIMINARY REPORT 0^ THE BOTANY OF CENTRAL COLO- 

 RADO. 



Leaviug Denver June 12, 1874? a few of tlie plants of the plains bor- 

 dering tlie foot-hills had already passed the proper period for collecting. 

 On all sides of us, however, were enough just ready to burst into bloom 

 to suggest abundant work for the indefatigable botanist of the party, 

 Prof John Wolf Just here I w ould remark that it is thought there were 

 but few plants in proper condition to collect that escaped his observa- 

 tion, and the good state of preservation in which the botanical stores 

 reached Washington is due entirely to the unusual care he bestowed 

 upon them. 



I will briefly indicate the botanist's route here, to save a continual 

 reference to it in the body of the report. From Denver the first impor- 

 tant point reached was Georgetown, via Apex, Clear Creek, and Idaho 

 Springs, The change from the flora of the plains to that of the mount- 

 ains may be considered as clearly defined at Apex. After leaving this 

 place, we began the ascent of the foot-hills, which in their estimated 

 average altitude of 8,000 feet afforded enough of variation in physical 

 conditions to outline, as it were, the botanical prospects for the season. 



After a halt of a few days at Georgetown, the party started, June 17, 

 for South Park, via the Argentine Pass, (altitude 13,000 feet,) Snake 

 Eiver, Breckenridge Pass, and Tarryall Creek, involving a crossing and 

 recrossing of the divide between the waters of the Platte and the Blue, 

 a tributary of the Colorado of the West, thus giving the opportunity for 

 making almost synchronous observations upon the flora over a range 

 in height of 4,500 feet; this, if we may transfer Humboldt's results 

 from Central Europe to the heart of our continent, being the equivalent 

 of nearly 17^ of latitude, going north from our starting-poiut. Prom 

 some collateral evidence I am led to think the estimate is not far from 

 correct. 



During the latter part of June and most of July the botanist was 

 busily engaged in South Park, having there the flat portion of the park, 

 with its soil composed of a mixture of sand and gravel and some loam, 

 on which to collect the plants of the open ground. Though isolated 

 from the plains, this portion of the park in some respects represented 

 the flora we should have had east of the foot-hills. The average eleva- 

 tion of the plain-like portion of South Park may be put down as about 

 9,800 feet above the sea. From this height up to almost 14,000 feet the 

 botanist could range through successive alpine zones of vegetation in 

 a single day. 



July 22, we left South Park, and on the 23d crossed Mosquito Pass, 

 thus allowing the observations taken on the Argentine Pass to be 

 repeated a month and a half later in the season. 



July 24, we camped at Twin Lakes, the altitude of which is about 

 9,100 feet. This was a specially fortunate center for botanical investi- 

 gation, allowing the quiet water on the lake-shore, the mountain-streams 

 pouring into the lake, the barren stretches of open ground along the 

 Arkansas, and the mountains to the west of camp, all to be readily 

 reached. The deep, shaded ravines, filled with moisture from the 

 streams, which rushed with headlong speed from precipice into chasm, 

 were favorite retreats for the mosses and well repaid the investigation 



