520 INDEX. 



Page. 



Pifion, Mexican 



single-leaf 



Pinus arizonica 



cembroides 



on 



chihualiuana 



coulter! ^^ 



edulis ^'^ 



00 

 maynana - 



monophylla 



ponderosa ^° 



sabiniana ^" 



strobiformis ^" 



torreyana ^° 



Pitahaya 65, 66 



dulce 66 



Plains mouse, Chihuahua 389 



San Diego - 3^8 



Sonora 384 



Western Desert ^ 394 



Plants gathered by the International Boundary Commission 130 



Platanus occidentalis '. 56 



racemosa 56 



wrighti 56 



Playas valleys 11, 15 



Populus angustifolia 47 



f remontii 48 



tremuloides 47 



wislizeni ' 48 



Post Spring, Fort Huachuca 102 



Pozo de Luis, Mexico 18, 19, 114, 115 



flora of 115 



Pozo Verde 113 



Mountains 113 



Prairie-dog, Arizona ■. 340 



short-tailed 345 



Pride of India; 69 



Prong-horn, Mexican 221 



Prong-horns 220 



Prosopis glandulosa 59 



odorata 59 



velutina 60 



PrunuB demissa '. 58 



ilicifolia 58 



integrifolia 58 



salicifolia 58 



Pseudotsuga mucronata 39 



Ptelia betulifolia 62 



cognata 62 



jucunda 62 



sancta 62 



trifoliata 62 



Puga, Guillermo B. y, International Boundary Commissioner 1 



Quaking asp 47 



