WHITE DAWNROSE 
Pachyloplus marginatus (Nuttall) Rydberg 
In the morning the dry sandy plains or mesas about Tucson ate 
dotted with the beautiful white flowets of the dawnrose. About noon 
the blossoms close, and, turning pink in fading, they soon disappear, 
a new bud opening next morning. The petals ate 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 
