PALO \'ERDE. 



167 



to all the species, and by which the name " palo verde " is verv 

 properly suggested, the name being Spanish for " green tree." 

 The tree usually grows quite plentifully upon the stony hillsides, 

 and in some places, at the time when other vegetation is less con- 

 spicuous than usual, has the aspect of a small apple tree, the 

 whole formation looking rather orchard-like. During the early 



Fig. 24. Parkiiisonia Torrcyaiia, Sierrita Aiountains, Arizona. (After a 

 photograph by Prof. V. 'SI. Spalding.) 



spring the smaller branches, which are lithe tapering twags, are 

 clothed with bipinnate leaves of a rather curious character. The 

 single leaf has a very short rachis. so small indeed as to escape 

 observation at first. From this spring two slender pinnae an 

 inch or so long, which bear six or eight minute orbicular pin- 

 nules, scarcely an eighth of an inch in diameter. So small are 

 the leaves that when they fall, as they do during the latter part 

 of April, very little difference is to be noted in the general aspect 

 of the tree, although of coiu^se this will depend upon the density 

 of the folia""e. which \'aries with diff'erent indii^-iduals. The 



