304 FORREST SHREVE 



at Bonita, showing that here, just as in the Santa Catalinas, the 

 first 1000 feet of mountain slope engender a marked rise in the 

 rainfall. The conditions which give the forested elevations of 

 the Santa Catalinas a much higher rainfall than the encinal 

 region appear to be reversed in the Pinalenos, where there is a 

 fall in the precipitation on ascending from the latter vegetation 

 at 7000 feet into the forest at 8000 feet, 



The vertical distribution of rainfall in the isolated mountains 

 of the southwest is not only of great theoretical interest to mete- 

 orology but is of fundamental importance in connection with 

 our knowledge of their vegetation, and also of practical value to 

 foresters with relation to forest management and the control of 

 fires. Any seasonal records that can be taken will be of great 

 value, as it will obviously be a long time before we can secure 

 data for the entire year at these uninhabited elevations. 



FLORA 



At the present time the floristic features of the Pinaleno Moun- 

 tains can be discussed only in a general way. The imperfect 

 knowledge of their flora may be judged by the fact that no 

 plants were collected in them after the visit of J. T. Rothrock, 

 with the Wheeler Expedition in 1874, until the first visit by the 

 writer in 1914. The most prominent differences between the 

 forested elevations of the Pinaleno and Santa Catalina Moun- 

 tains lie in the existence of a group of subalpine species in the 

 former, for which there are- no favorable altitudes in the latter; 

 and in the existence of a few species at lower elevations in the 

 former which have failed to make their way to the latter. The 

 Pinaleno Mountains are also without many of the desert and 

 encinal species of the Santa Catalina Mountains. 



The most prominent of the subalpine plants found in the 

 Pinaleno range but absent from the Santa Catalinas are : 



Alnus tenuifolia Nutt. 

 Callha leptosepala DC. 

 Campanula parryi Gray 

 Chimaphila umbellata (L.) Nutt. 

 Gentiana elegans A. Nels. 



