Sy AGENESIA. iEqUAllS. 129 



A genus of 2 species indigenous to Europe. 



■^37. CYNAUA. X. (Artichoke.) 



Calix dilated, imbricate, scales carnose, 

 emarginate with a point. Receptacle setose. 

 Pappus sessile, plumose. 



Leaves large, similar to those of ^5cfini/i?«pinnatifid and 

 spiny. 



Species. 1. C Sculyintis. (Common Artichoke.) Begin- 

 ning to be naturalized tmd proving a troublesome weed in 

 some parts of Virginia. — Indigenous to the south of Eu- 

 rope. 



538. CARDUUS. Z. (Thistle.) 



Calix ventricose, imbricate, scales spiny. 

 Receptacle villous. Pappus pilose or plumose, 

 deciduous. 



Leaves usually spiny, decurrent or sessile. Stignia 

 nearly entire. Anther's bifid at the base, the segments 

 simple or pencillate. Seeds smooth and shining. Pappus 

 articulated to a glandular ring. 



Species. 1. C. pcctinatus. -f-. 



§ II. Cnicus. Pappus plumose, 



2. lanceolatits. Naturalized. 3. aUissimns . On the allu- 

 vions of the Missouri, not far from St. Charles, I have ob- 

 served this thistle 12 to 18 feet high. 4- arvensis. Not 

 commonly naturalized. Abundant round Detroit. I have 

 never seen it in Pennsylvania. 5. muticns. 



6. * glaber. Leaves sessile, pinnatifid, every where 

 smooth, segments spiny, acute, lower ones subdecurrent; 

 calix ovate, glabrous, "scales spineless, shortly and seta- 

 ceously mucronate, obtusely carinate; stem much branch- 

 ed. Hab. In New Jersey, Allied to C. muticns. 4> or 5 

 feet high and slenderly branched. 



7. virginiaiius. Stem attenuated, mostly 1 -flowered; 

 leaves sessile, lanceolate-iiiieari margin revolute, distantly 

 and spinosely serrate, beneath tomcntose, above very 

 smooth; calix ovate, scales appressed, sliortly mucronate, 

 carinate, carina glandulous. Hab. In the forests of North 

 and South Carohna, common. Stem 3 or 5 feet high, slen- 

 der, attenuating nearly into a solitary and almost naked 

 peduncle; flower purple, somewhat larger than that of V. 

 arvmisis. Leaves uumerous towards the base of the stem. 



