i88 



BOTANICAL GAZETTE 



[march 



In southwestern Nebraska our work was begun in seasons, 1907 

 and 1908, forming the conclusion of a series of wet years. This 

 was followed by a prolonged dry period, reaching its climax in 



TABLE I 

 Relation of annual precipitation at Lincoln, year by year, to normal 



(=100), 27.51 INCHES, showing RELATIVE DRYNESS OF PERIOD OF 



observation (1906 TO 191 2). 



1910-1911, the precipitation in 1910 being the lowest recorded 

 since observations were begun at North Platte 42 years ago (table 

 II). By 191 1 the subsoil moisture had probably been reduced to as 



TABLE II 

 Annual precipitation in inches at stations in southwestern Nebraska 



Length of record in years* 



McCook 

 16 



Wauneta 

 27 



Imperial 

 26 



H. O. Ranch 

 II 



North Platte 



42 



Normal 



1905 



1906 



1907 



1908 



1909 



1910 



1911. . .' 



1912 



1913 



1914 



1915 



1916 



Maximum. . 



Minimum. . . 



*To end of 1916. 



19.71 



33-97 

 20.59 

 19.32 

 18.08 

 22.54 



9-34 

 12. 15 

 14.69 

 18.26 

 18. 24 

 30 -95 

 15-35 

 33-97 



9-34 



18.70 

 32.24 

 22.82 

 20.18 

 24.77 

 18.46 

 13-82 

 18.82 

 20.00 

 16.05 

 17.26 

 27.04 



14-95 

 32.24 



13-82 



20. 79 



33-05 

 26. 23 

 16. 76 

 26. 27 

 20.03 

 11.77 



17-37 

 24.58 

 16.60 

 16.94 

 37-14 

 19-33 

 37-14 

 11.77 



17.80 



20.14 

 12.02 

 21 .01 

 16.89 

 7.62 

 12. 76 

 20.74 

 14.99 

 19.42 



35-84 

 14.60 



35-84 

 7.62 



18.88 

 26.81 

 27.99 

 19.61 

 19.96 

 22.41 

 10. 70 



17-43 

 18.69 

 19. 10 



15-79 

 32.70 

 12.96 

 32.70 

 10.70 



low a point as is ever experienced in southwestern Nebraska. The 

 climate of the Nebraska portion of the Transition Region, including 

 both groups of fields, has been discussed in some detail in a previous 

 paper dealing with the composition of its loess soils (2). 



