164 INTRODUCED PLANTS. 



In the list there are thirty-six species, representing 

 twenty-nine genera and fourteen orders. A professional 

 botanist might doubtless have obtained a larger list. 

 One of these plants (Microseris Douglasii, Gray), never 

 refound since its discovery nearly fifty years ago, turns 

 up here in eastern Massachusetts ! Some unknown sheep 

 certainly deserves botanical honors ! 



Most of these plants were identified by Sereno Watson, 

 Ph. D. ; also to Mr. L. J. Hastings, of North Chelmsford, 

 special acknowledgments for assistance are due. 



A few of the species in the following list grow in New 

 England and even in Middlesex county. But none of 

 them are found in the immediate vicinity under consider- 

 ation, and there can be no question that all below were 

 sown by wool ; and that, whatever be their original habitat 

 they came to this locality, with possibly an exception 

 or two, via California, whence is received seven-eighths 

 of the wool " handled " and where nearly every plant 

 mentioned has been recorded as growing. In the list, 

 special scarcity or abundance is noted. 



CRUCIFERJS. 



1. Sisymbrium incisum, Engel. 



2. Tropidocarpum gracile, Hook. 



GERANIACE^. 



3. Erodium cicutarium, UHer. 



Abundant and spreading. This plant seems to be a native of 

 the Pacific coast of both Americas, but may have found its way 

 thither from Europe, which has been considered its home. It 

 grows about woollen mills in New England, and is occasionally 

 found in New York and Pennsylvania. The twisted and 

 bearded styles greatly favor the dispersion of its seeds by the 

 fleeces of sheep. 



LEGUMINOS^. 



4. Medicago denticulata, Wild. 



Eastern States ; adventive from Europe. 



