1 66 



THE PLANT WORLD. 



and p. Torrcyana. According to Sudworth's check list of forest 

 trees of the United States,* the name Ccrcidiuiii Torrcyaiuim 

 (Wats.) Sarg-ent, is given to the last mentioned species, but for 

 reasons of which I shall speak later it would hardly seem justi- 

 fiable to separate generically P. Torrcyana from the other two 

 species. 



Fig. 22,. Parkinsoida luicrophylla in Blossom. 



I shall describe first the small leaved palo verde ( Parkiiiscviia 

 micro phxlla) (Fig. 23), which is found growing upon the rocky 

 foothills of southern Arizona, California and Sonora, Mexico. 

 This plant is as distinctly characteristic of this habitat as are the 

 ■Giant cactus or Suguaro, the Ocotillo ( Foiujincna splciulcns) 

 and a considerable number of other i)lants, which in this con- 

 nection need not be mentioned. It is a small, somewhat irregular 

 tree, ten or twelve feet high, with more or less twisted and con- 

 torted liml)s clothed with a green bark, this featiu-e being common 



* Bulletin No. 17, U. S. Dept. of Agriculture, Division of Forestry, i8;)8. 



