64 IOWA ACADEMY OF SCIENCES. 



only a few shrubs like Si/mj)horicarpos racemosiis, a few 

 Prunus demissa and a great deal of sage brush {Artewisia 

 tridentata), the plant growing from four to six feet high. 

 The sage brush is naturally scattered, and around the base 

 of the branches grasses like Stipa comata, S. robusfa and 

 Agropyron occideniale, occur. In the open places Orflio- 

 carpus, Castilleia. Erigonuni umheUahim, Lupinus argoplnjl- 

 Ins are abundant; also two species of Bigeloria. Rising 

 from the third flood plain thei'e occurs what is commonly 

 called a bench. These rise several hundred feet above the 

 flood plain. The benches generally contain few shrubs or 

 trees, except where the timbered belt begins. They are 

 cut by narrow canons whose sides contain such shrubs as 

 Amelanchier alni folia, Eosa Fendleri, Acer glabrum, Cerco- 

 carpus pjarvifoUus. Groves of Populus tremuloides, and 

 occasionally, near the timber belt, Pseudotsuga Douglasii. 

 Near the bases of these canons alkaline springs occur. 

 Salix Macke}iziana, S. Bebhiana are usually common in 

 such places, accompanied by such plants as Aconituni 

 Colnmbianum, Aster, Erigeron,, Bromus Porteri, Plantago, 

 PJileum alpinu}n, Mimulus Jaiitesii, and Castilleia. The 

 slopes of these benches likewise contain the Amelanchier, 

 Cercocarjjus, and where the benches are dry, Juniperus occi- 

 dentalis var nionospeniia. 



During our stay at this camp the temperature was by no 

 means excessive. The highest temperature recorded from 

 July 11th to llth was 95^ F. The highest soil tempera- 

 ture, two inches down in the soil on the second flood plain, 

 w^as 69.5 "^ F. The highest record for the third flood plain 

 was 85 °F. At a depth of one foot in the third flood plain 

 the highest record was 68° F.; on the third bench it was 

 78° F. 



The marked conditions of the flora of Black's Fork at 

 an altitude of 7,500 feet is as follows: First a mesophytic 

 willow formation consisting of Salix sfricta, S. lutea, S. car- 

 data and S. lasiaudra var caudata, Popnhis tremuloides, P. 

 a)igustif<)H<i. Ahius incana var virescens, Betula occidentalis 

 and a small number of hydrophytic species. This consti- 

 tutes the most recent formation. This is succeeded by 



