SYNGENESIA P. ^QUALIS. 179 



241. CNICUS. 



* Leaves decurrent. Stem winged. 



1. C. lanceolate stem furrowed, hairy ; leaves decurrent, pin- 

 natifid, hispid, with variously spreading spinous lobes ; calyx 

 ovate, shaggy ; flowers erect, large, crimson. Spear Thistle. 



Hob. Way-sides frequent. July, Aug. $ 



3. C. palustris, very prickly, green, 3 or 4 feet high ; leaves de- 

 current, pinnatifid, toothed, spinous, rough ; flowers aggregate, 

 sessile, purple or white, rather small ; calyx ovate, minutely 

 spinous, nearly smooth. Marsh Thistle. 



Hab. Moist meadows and shady places. July. <J 



* * Leaves sessile, or partially decurrent Stem not winged. 



3. C. arvensis, stem panicled, solid ; leaves sessile, pinnatifid, 

 spinous, nearly smooth ; calyx ovate, outer scales spinous ; 

 flowers stalked, pale purple ; root creeping, tuberous. Creeping 

 Thistle. 



Hab. Cultivated fields and way-sides. July. I/. 



A very bad weed, which it seems quite impossible wholly to 

 destroy by any exertions of tillage which are consistent 

 with due attention to profit. 



4. C. heterophyllus, stem downy, almost single-flowered ; leaves 

 clasping the stem, fringed, undivided or pinnatifid, very smooth 

 above, densely cottony beneath ; flower large, fine purple. Me- 

 lancholy Thistle. 



Hab. Moist mountainous pastures. " At the foot of Che- 

 viot," Winch. July, Aug. 7/ 



242. ONOPOKDUM. 



1. O. Acanthium, cottony, 4 or 5 feet high ; leaves ovate-ob- 

 long, sinuated, woolly on both sides ; calyx-scales awl-shaped, 

 spreading in every direction ; flowers solitary, large, bluish rose- 

 colour. Common Cotton-thistle. 



2 



