COMPOSITE. 173 



smooth above, tomentose beneath ; involucre ovate ; scales appressed, 

 shortly mucronate, carinate. Cnicus virginianus Pursh. Cirsium tir- 

 ginianum Mich. 



HAB. Woods. Penn. to Car. July Sept, U -Skew* 23 



feet high, covered with a white down, especially towards the 



summit. Flowers solitary, terminal, purple. 



6. C. discolor Nutt. : stem divaricately branched ; leaves lanceolate, 

 sessile or clasping, more or less deeply pinnatifid, smooth above, tomen- 

 tose beneath ; segments 2-lobed, ciliate and spinous ; involucre sub- 

 globose ; scales ovate, spinous. Cnicus discolor MuhL 



HAB. Margins of swamps. N. J. to Car. July, Aug. $. 

 Stem 36 feet high, hairy and tomentose ; branches leafy. 

 Leaves long. Floicers solitary, middle-sized, purple. 



7. C. pumilus Nutt. : stem hairy, few-flowered ; leaves clasping, 

 green on both sides, oblong-lanceolate and pinnatifid ; segments irregu- 

 larly lobed, ciliate and spinous ; involucre large, and somewhat globose, 

 naked ; scales appressed, lanceolate, acuminate, spinous. 



HAB. Dry fields. N. S. $. Stem 1 2 feet high, erect or 

 subdecumbent. Leaves large, the lowest often 12 inches long. 

 Flowers few, very large, purple. Pappus more than an inch in 

 length. Nuttall describes a variety of this species with the stem 

 simple, 1-flowered, and the leaves densely margined with spines. 

 It occurs on the banks of the Hudson near the city of New- 

 York, and is called var. hystrix. 



8 C. spinosissimus Walt. : leaves sessile, pinnatifid, acutely incised, 

 very spinous, woolly beneath ; flowers crowded, bracteate ; bracts very 

 spinous, the spines generally in pairs ; involucre unarmed. Cnicus 

 Jtorridulus Pursh. 



HAB. Fields. N. S. to Car. July Sept. l[.Stem 23 feet 

 high, hollow. Flowers axillary and terminal, large, yellowish- 

 white, (pale purple Elliott.) Bracts 20 or 30 round the base of 

 each flower, on the outer ones spines in pairs. Scales of the 

 involucre lanceolate, very acute, but scarcely spiny. 



9. C. glutinosus Beck : leaves pinnatifid, with divaricate segments ; 

 involucre ovate, with unarmed glutinous scales. Cnicus glutinosus 

 Big. 



HAB. Damp soils. Mass. Aug., Sept. $ Stem 4 6 feet 

 high, branching. Leaves sessile, somewhat clasping. Flowers 

 small, on slender stalks, deep purple.-r- Allied to C. muticus, but 

 differs by its leaves and by the ovate glutinous scales of the in- 

 volucre. 



12. ONOPORDON. Linn. 



Involucre ventricose, with the scales spreading and spinous. 

 Receptacle pitted. Pappus deciduous, rough. 



Syngenesia. 

 15* 



