INTRODUCED PLANTS. 163 



In a village near Lowell — North Chelmsford, Mid- 

 dlesex Co., Mass. — is a wool-scouring establishment. 

 Hither are sent, for cleansing, bales of fleece from many 

 regions of the world, but mostly from California. That 

 which comes from the latter country is peculiarly "shiveyj 

 or full of seeds and other foreign substances. The dirt, 

 which is blown or washed from the wool is thrown into 

 pits and the foul suds are pumped upon the mass which 

 is thus converted into manure. The solid refuse, in this 

 way utilized, consists largely of two kinds of burs which 

 have become so familiar to "wool-scourers" as to obtain 

 technical names, the burs of Xanthium strumarium being 

 called "mestizoes ," and the spiral pods of Medicago den- 

 ticulata, " alfaquas" Along with these are man}' other 

 kinds of seeds, all of which are more or less concealed in 

 the fuzzy masses of refuse. In the process of dumping 

 this waste into the pits, these seed masses are somewhat 

 scattered, as they also are by the wind and other agencies. 

 Many germs, too, survive in the manure. 



The writer resided in North Chelmsford from 1878 to 

 1880, but most of the following plants were collected 

 during the summer of 1878 when his daily walk to the 

 post office took him through this botanic garden. Pre- 

 vious to that season, a piece of ground around the pits 

 had been manured heavily with this compost and "seeded 

 down" to grass. This land produced quite abundantly 

 many of the following plants, especially the Borragi- 

 naceae, Composite, Grasses, and Erodium cicutarium. 

 Business being dull that summer and the weather being 

 favorable, the edges of the pits produced certain species 

 more abundantly than either subsequent summer. 



The soil of the village is a sand which becomes very 

 hot and dry under a summer sun, and may afford special 

 Californiaii conditions. 



