Aug. 7, 1916 



Vegetative Succession Under Irrigation 



757 



years, and oats often fail to mature. Besides, grain can not be grown in- 

 definitely on the same land, even virgin land, without rotation. In the sec- 

 ond place, the expenses of growing the cultivated crops are far greater 

 than those of growing the uncultivated. The farmer who grows a natural 

 meadow even by controlled irrigation as outlined above, ultimately will 

 have less expense than the farmer who grows grain or alfalfa and continu- 

 ally has to repair ditches and regulate the water supply. Besides, he 

 has not only been saved the initial cost of buying seed and of preparing 

 a seed bed but he has also been able to utilize his entire upland, for all 

 of it is potentially a meadowland. 



These conclusions apply only to farming under the climatic conditions 

 that exist at Rock Creek. At lower altitudes, where conditions are less 

 rigorous and where cultivated crops well suited to the region have been 

 long grown, this method of raising hay can not be too strongly con- 

 demned. It could be used with success only where hundreds of acres 

 were available. 



Even at Rock Creek on a smaller scale it would mean a criminal 

 waste of land and water, as the ranch company is even now drawing so 

 heavily on its reservoirs and on Rock Creek that during a dry season 

 some of its meadows suffer. The owners have about reached the limit 

 of increasing their hay yield by the growth of more natural meadows. Al- 

 falfa gave much greater yields than the natural vegetation, and Briggs 

 and Shantz have shown that alfalfa has a water requirement of only 831 

 units for every unit of dry weight produced. Further augmentation 

 can come only by the raising of crops that require less water and give 

 greater yields to the acre in return. The recent perfecting of grains 

 and hays adapted to the high altitude and short season of the Laramie 

 Plains will soon make this method of farming infeasible even under 

 such conditions as those of Rock Creek. 



MINOR PLANTS 



Below are lists of those plants occurring in the Rock Creek region 

 which have not been mentioned in the body of this paper, being mostly 

 of interest to botanists only. 



BENCH LAND 



Allium cemuum Roth. 



A Ilium textile Nels. and Macbr. 



Eriogonum ovalifolium Nutt. 



Eriogonum flavum Nutt. 



Paronychia sessilifolia Nutt., var. brevi- 



cuspis A. Nels. 

 Lesquerella condensata A. Nels. 

 Lesquerella montana (Gray) Wats. 

 Astragalus Drummondii Dougl. 

 Astragalus missouriensis Nutt. 

 Astragalus nilidtcs Dougl. 

 Astragalus Purshii Dougl. 

 Astragalus Shortianus Nutt. 



Euphorbia montana Engelm. 



Opuntia polyacantha Haw. 



Cogswellia orientalis Jones. 



Gilia pungens (Torr.) Benth. 



Gilia spicata Nutt. 



Phlox glabrata (E. Nels.) Brand. 



Oreocarya fiavoculata A. Nels. 



Oreocarya thyrsiflora Greene. 



Chrysopsis villosa Nutt. 



Erigeron Eatonii Gray. 



Sideranthus grindelioides (Nutt.) Britton. 



Stenotus acaulis Nutt. 



