122 PLANTS OF MASSACHUSETTS. 



Carduus. L. 17. 1. 



A numerous genus, from which a large number of species was 

 separated under the generic name, Cnicus, by Willdenow. Both 

 names are derived from words which mean points or prickles, as 

 the plants are usually full of prickles or spears. Of more 

 than 100 species, the far greater portion belong to Europe, about 

 a dozen to North America, and 7 are found in Massachusetts. 

 They are here ranked undjer Carduus, and have little beauty ; 

 most are weeds, and some very troublesome. 



C. discolor, Muhl., and C. lanceolatus, W., are the Common 

 Thistles of our fields, the latter being found in waste places and 

 along fences, and much more abundant than the other ; its heads 

 of flowers are rather smaller and with more tapering cones. The 

 latter was introduced from Europe, but the former is a native 

 of this country, and has been cultivated in some of the great 

 gardens of England. 



C. glutinosus. Big. One of the handsomest species ; in damp, 

 rich soils ; August, and biennial. Big. 



C. altissimus. W. Tall Thistle. Another native of this 

 country, 6-10 feet high, not very rough ; meadows ; August. 



C. horridulus, Ph., and C. pumilus, Nutt., are found in the 

 vicinity of Boston. Big. 



C. arvensis. L. Canada Thistle. From its being propa- 

 gated from Canada southwards ; the common field thistle in Eu- 

 rope, as well as Canada and the Northern States. Within the 

 memory of men now living, this plant came into the northern part 

 of Vermont and New York, and has since spread to the south 

 part of New England and New York. In 1818 it had not been 

 seen by Nuttall in Pennsylvania, and was not in the " Plants of 

 Chester County, Pennsylvania," published by Dr. Darlington, 

 in 1826. By some it has been supposed, that its seeds were 

 wafted across the Atlantic from the North of Europe by winds. 



