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 MUHLENBERGIA 



NOTES ON SOME INTRODUCED PLANTS 

 OF SOUTHERN CALIFORNIA— -II 



By S. P. Parish 



Prick i.n' LKTTUCE 

 Lactuca Scariola L. var. integrata Gren. and Godr. Fl. 

 France 2: 230. 1850. Only this variety has been found on the 

 Pacific coast, and it is the plant which has become so widely 

 spread throughout the United States. It is distinguished by its 

 spinulose toothed leaves. The species, which has mucin ate or 

 pinnatelv lobed leaves, is common only in the region about Cin- 

 cinnati. The correct identification of these plants was first 

 pointed out he Dewey, Rhodora 7: 9-12. 1902. This is a strik- 

 ing example of the rapidity with which an introduced weed may 

 overspread a continent. Its first appearance was in 1835, when 

 a few plants were found near Cambridge, Mass., ( 1 4) and its 

 early progress must have been slow, fur thirteen years later, ac- 

 cording to the 5th edition of Gray's Manual ( 1 S 7 f > ) , it was still 

 known only from Cambridge^ where it was "adventive; in waste 

 grounds and by roadsides." By 1884, however, it was "becom- 

 ing common in the Atlantic states, in waste grounds near towns 

 and habitations," (15) and in the same year it appears in a list 

 of recent additions to the flora of Richmond county, X. V. 1 16). 

 In the next decade it made a rapid conquest of the middle west, 

 and the botanical journals contain frequent records of its appear- 

 ance at places in those states. Usually it is reported as growing 

 in some particular spot, along railways or roads, indicating that 

 its introduction had been too recent for much diffusion. Tims 



(14) P. IP Dewey, Pot. (Pi/. •><>: 3m. [895. 



(15) Gray, Svn. Fl. 1: Part 2, 442. 



(16) Hollick and Pritton, Bull. Tott. Club, 18:83. [884. 



(121I 



