WHITE DAWNROSE 



Pachyloplus marginatus (Nuttall) Rydberg 



In the morning the dry sandy plains or mesas about Tucson are 

 dotted with the beautiful white flowers of the dawnrose. About noon 

 the blossoms close, and, turning pink in fading, they soon disappear, 

 a new bud opening next morning. The petals are so ethereal in their 

 delicate loveliness that it is hard to understand how they can spring 

 from such an unfriendly dry soil. 



White dawnrose ranges from Colorado, Utah, and Arizona to Idaho 

 and Oregon. 



The specimens sketched were gathered about forty miles south of 

 Tucson, Arizona. 



PLATE 387 



