224 East and West 
desert plant bristling at all points. Perhaps 
the typical tree is the palo verde or green- 
barked acacia (Cercidium torreyanum) with 
its minute leaves and its conspicuous pale 
green bark. Parkinsonia microphylla re- 
sembles it and is also called palo verde but 
its bark is of a yellower green and its leaves 
even more minute. Both trees appear leaf- 
less at a little distance. Unlike the palo verde 
the parkinsonia has no thorns, but as if to 
atone for this, its twigs end in spines. 
As the leaves diminish, the spines or thorns 
appear to increase, and the canotia is abso- 
lutely leafless while its twigs are merely very 
long spines. It is this species (Canotia hola- 
cantha) which is called the ‘‘Thorn of Pales- 
tine.’”’ Probably the name was given it by 
the early Spanish settlers and the tradition 
of its identity with the Syrian tree was per- 
petuated by the unbotanical; for Sargent gives 
the tree a purely American habitat. Such 
a tradition might very naturally have arisen 
among the Spaniards and readily have been 
handed down. Of the genus Acacia there is 
the cat’s-claw, a scraggly shrub, whose thorns 
cause one more trouble than the barbs of the 
cholla, for the simple reason that the cholla 
is habitually avoided as if by instinct, whereas 
