88 CRUISE OF THE BARRERA 



wrong beyond the creation of those terms by man? 

 In the vegetable kingdom we may assume that the 

 life process goes on guided only by that invisible, 

 unknowable force within, and free from any 

 possible influence of mental perversion, and yet 

 for this vine to reach its maturity and bear seed 

 it must destroy another life, and this without 

 animus or enmity or the excuse of self-defense. It 

 is a wholly unconscious process. Nature study 

 forces the conclusion that "right" and "wrong" 

 are social rather than natural considerations. 



I have already referred to some of the commoner 

 thorny plants of the sierra, but one is so devilish 

 in its ingenious arrangement of spines that I must 

 mention it. This is the Malpighia urens, a large 

 shrub with lanceolate leaves which carry upon their 

 borders small forked spines pointing in two direc- 

 tions and delicately attached to the leaf edge by 

 the slenderest thread. These become detached by 

 the slightest touch and painfully injure the flesh. 

 There is also one other "aggressive" plant fre- 

 quently encountered about the base of the sierra 

 — the "cow-itch" {Mucuna priiriens). This vil- 

 lainous ground-creeper bears a fuzzy brown seed 

 pod liberally sprinkled with microscopic spicules. 



