186 Class XIX. Order I. 



chanism for dispersing the seeds. Common in waste and cul- 

 tivated ground, July, August. Perennial. 



223. CNICUS. 

 CNICUS ARVENSIS. Willd. Canada Thistle, 



Leaves sessile, pinnatifid, spinous ; stem pan- 

 icled ; calyx ovate, its spines minute ; down feath- 

 ery, Sm. 



Syn. CARDUUS ARVENSIS. Sm. 



SERRAfULA ARVENSIS. L. 



This species is easily distinguished from the rest of our 

 thistles by its small flowers, and its thornless calyx scales. It 

 commonly forms beds by its perennial, creeping roots, and is 

 exceedingly difficult to extirpate. The stems are two or three 

 feet high, smooth, many flowered. Leaves alternate, sessile, 

 pinnatifid, with numerous lobes, and very thorny. Flowers ter- 

 minal, purple ; the scales of the calyx ending in a short, ^yeak 

 bristle, rather than a spine. This plant seems to have come to 

 us from the westward, where it is exceedingly troublesome. 

 The name of Cursed thistle has been given it in England. Ju- 



iy. 



CNICUS LANCEOLATUS. Willd. Spear Thistle, 



Leaves decurrent, pinnatifid, hispid ; the seg- 

 ments divaricate ; calyx ovate, villous ; stem hairy, 

 Sm. 



Syn. CARDUUS LANCEOLATUS. L. 



Very common by road sides and in waste ground, usually 

 three or four feet in height. Stem upright, furrowe;!, hairy, 

 and winged by the decurrent base of the leaves. Leaves white 

 and woolly underneath, pinnatifid, half the lobes divaricated, tipt 

 with long and very acute spines. Flowers terminal, purple, 

 numerous, above the middle size. Calyx ovate, contracted to 



