Volume 5 September 30, 1909 



MUHLENBERGIA 



LIBRAI 



NOTES ON SOME INTRODUCED PLANTS NEW YO 



OF SOUTHERN CALIFORNIA— I botanic 



By S. B. Parish Ga 



In the first and second volumes of Zoe (1890-91) I contrib- 

 uted a series of papers discussing, in some detail, the introduced 

 flora of southern California. Eighteen years have elapsed since 

 those papers were printed, a short period in the history of a 

 plant population; vet within it have occurred instances of the 

 rapid dissemination of some new-comers, as well as of the fail- 

 ures, partial or complete, of some weeds which are elsewhere 

 very common, to have established themselves. In the present 

 paper* I shall confine myself to a consideration of certain cases 

 of the character above indicated, and to a notice of a few plants 

 of recent arrival. 



Ax Invasion OF BROMES 



In one of the papers in Zoe I recorded the very recent in- 

 troduction, on opposite sides of San Bernardino valley, of Bio- 

 mus rubens and />. maximus var. Gussoni. These broines were 

 first noticed in the spring of 1888. In each instance there was 

 but a small number of plants, which could have first appeared, 

 at most, not more than two years earlier, and both owed their 

 introduction to foul seed grain. Two years after they were first 

 noticed, each species had spread for a mile along the roadsides 

 of the two canyons in which they first appeared, and a few plants 

 of one species were noticed in the valley itself. The diffusion 

 of both broines continued with increasing rapiditv, and in a very 

 few years large patches of either could be found in all parts of 

 the valley and the surrounding hills. They are now among the 

 most wide-spread, abundant and well established grasses of the 



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