COMPOUND FLOWERS. 351 



are often of a brownish hue. Fl. July, August. Bien- 

 nial. 



3. C. arvensis (Creeping Plume-Thistle). Heads of 

 flowers numerous, stalked, egg-shaped ; scales of the 

 involucre closely pressed, pointed, but scarcely thorny ; 

 stem not winged; root creeping. Border of fields ; very 

 common. A handsome weed, about two feet high ; the 

 flowers, which grow in a corymbose manner, are of a 

 light purple colour, and smell like those of the Musk 

 Thistle. Fl. July. Perennial. 



4. C. pratensis (Meadow Plume-Thistle). Heads of 

 flowers mostly solitary ; stem-leaves few, soft, and wavy. 

 Moist meadows ; not general. A small plant, 12 

 18 inches high, with a cottony stem, bearing a few leaves, 

 and rarely more than one small purple flower. Fl. July. 

 Perennial. 



5. C. acaulis (Dwarf Plume-Thistle). Heads of 

 flowers solitary and stemless, or nearly so. Dry gravelly 

 or chalky pastures : not general, but in some places 

 very abundant, and a pernicious weed. A low plant, 

 consisting of a few thorny leaves, and a single, almost 

 stemless, purple flower ', by which character it is readily 

 distinguished from all the rest of the Thistle Tribe. 

 FL July, August. Perennial. 



* Less common species of Cnicus are C. eriophorus 

 (Woolly-headed Plume-Thistle), distinguished by the 

 thick white wool which clothes the scales of the very 

 large flowers : C. tuberosus (Tuberous Plume-Thistle), 

 which grows only in Wiltshire, an erect single-stemmed 

 plant, with a single, large purple flower : C. heterophyllus 

 (Melancholy Plume-Thistle), a mountain plant, with an 

 erect, cottony stem, and a single, handsome, purple 

 flower. 



19. ONOPORDUM (Cotton Thistle). 



1. 0. Acdnthium (Scotch Thistle). The commonest 

 of the thistle-tribe, abounding ' in waste ground, and 



