THE AMERICAN BOTANIST 43 



associated with Mormon settlements as to be known as the 

 Mormon tree. No other tree in the desert seems to thrive so 

 well. A list of the other shade-trees includes the Arizona Cot- 

 tonwood, mull)erry, catalpa, ailanthus, osage orange, and hon- 

 ey locust. One of the principal industries of the region is that 

 of fruit growing. Apples are extensively planted and in smal- 

 ler numbers' are found peaches, apricots, pears, almonds, and 

 occasionally a cherry. I saw no cultivated plums but a wild 

 plum (Primus Americano) clustered close to the cultivated 

 fields may have served as a substitute. 



One of the surprising things connected with the flora is the 

 fact that exclusive of cultivated plants, fewer than seventy- 

 five species, practically all of which are weeds of wide distri- 

 bution, are found in the oasis. One seems warranted in the 

 inference that cultivation of the soil has destroyed such native 

 plants as once existed and made room for the usual companions 

 of our cultivated crops. More than thirty percent are of Old 

 World origin and forty percent of the others are American 

 plants of wide distribution, at least in the western half of our 

 country. Only a mere handful have been derived from near- 

 by regions or from the desert, notwithstanding the intimate 

 contact of the two areas. Only four species have fruit adapt- 

 ed to being distributed by birds, and three others possess burs 

 which might be distributed by animals. All the rest are adapt- 

 ed for wind distribution, being either winged, equipped with 

 a pappus, having dustlike seeds, or of the form known as tum- 

 ble-w^eeds 



The plants in this list have been kindly identified for me by 

 Dr. P. A. Rydberg of the New York Botanical Garden whose 

 familiarity with western plants is attested in his "Flora of the 

 Rocky Mountains" and other publications. The names here 

 used differ in some respects from those sanctioned by the Vi- 



