2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 6l 



This species is common in the Colorado Delta as far north as Yuma, 

 Arizona, and is also found around springs and wells in the Cahuilla 

 Basin, around Salton Lake. 



This tree is especially characterized by its broad leaves, with nearly 

 truncate bases and shallow-toothed margins. It is most nearly related 

 to Populus fremontii, but is of much lower stature, with more pubes- 

 cent branches and with leaves of different shape and toothing. It is 

 named for Dr. D. T. MacDougal, who first brought it to my 

 attention. 



The illustration used here is from a photograph taken by Dr. D. T. 

 MacDougal at Colonia Lerdo, February, 1904. 



