WILD OATS AND ALFILERILLA. 41 



deterioration in another way. The reduction in the number of plants 

 leaves so much more nutriment and space available for the growth of 

 weeds and other less valuable species. Weeds invariably follow the 

 introduction of stock, into a country. B3 7 range weeds we mean any 

 plants of thrifty, vigorous habit, which are distasteful to stock. Just 

 as certainly as the selection by cattle of the choicest plants makes it 

 difficult for them to maintain a foothold, so surel}' does the same 

 process of selection allow the weeds every opportunity to increase, by 

 maturing and scattering seed without let or hindrance. 



These weeds are largely alien species, introduced chiefly b} T acci- 

 dent, with the advent of the white man, or along with the domestic 

 plants and animals introduced by him at a later date. They are often 

 plants which have become hardened to much more adverse conditions 

 of soil and climate than they find in California, and therefore grow 

 with greater luxuriance and spread with greater rapidity than species 

 which have, by long continuance under uniformly favorable condi- 

 tions, shown a tendency- to "run out" or to deteriorate. The struggle 

 for existence seems to be as keen among plants as among human 

 beings, and if one species or race is killed out by its animal or other 

 enemies, another race, less liable to attack by the same kind of enemy, 

 steps in to fill the space. Under these conditions it is evident that 

 on an overstocked annual range those species which are especially 

 palatable to stock will have little chance to propagate their kind. 



Wild oats and alfilerilla. — If the destruction of the most palatable 

 forage plants by selection is constantly going on, how could such pala- 

 table species as wild oats and alfilerilla ever have become so abund- 

 antly naturalized as to be the prevailing plants on the ranges in the 

 relatively short time since the Spanish occupation of California? And 

 if the} 7 had at one time been able to establish themselves as aliens 

 would not the same factor which enabled them to establish them- 

 selves prevent their being killed out by pasturing at a later date? 

 Is it not more probable that they are indigenous species, which have 

 suffered numerical diminution in the same way as have the wild clo- 

 vers? Such are the questions asked in this connection. We are not 

 at present prepared to answer them decisively, but to an3 T one who 

 has watched the spread of introduced weeds in California, especially 

 those from the Mediterranean region, the exotic origin and rapid 

 increase of wild oats and alfilerilla will not appear improbable, even 

 in the face of general range deterioration. Usually European weeds 

 find themselves quite at home on the soil of this State, new to them, 

 and comparatively unimpoverished. Annual species, especially, 

 spread with great rapidity. If the wild oats and alfilerilla were intro- 

 duced at the time of the Spanish occupation, when cattle were com- 

 paratively few in the land, they would have abundant opportunity to 

 "take" the country in spite of being relished by stock. Later, how- 

 ever, as cattle multiplied, and sheep were introduced, forage became 



