PLATE 3 
A. —Giant cactus and paloverde association. A more level area showing Car- 
negiea gigantea (Engelm.) Britton & Rose, Cercidium torreyanum (S. Wats.) Sarg., 
Olneya tesota A. Gray, Opuntia bigelovii Engelm., Covillea glutinosa (Engelm.) 
Eydb., Franseria dumosa A. Gray, etc. Near Sacaton, Ariz., March 13, 1915. 
B. —Creosote bush association. A pure stand of CovUlea glutinosa (Engelm.) 
Rydb., with wide spaces of bare soil between the plants and, in the background, 
a very few associated shrubs. Nipton, Calif., September 14, 1915. 
