COMPOSITE. 203 



Low grounds. Can. to Louis. W. to Texas. Aug., Sept. Q 

 3 5 feet high, striate and angular. Heads middle-sized, terminal. Flowers 

 purple. Awnkss Thistle. 



6. C. puwilum Spreng. : stem low, hairy, 1 3-flowered ; leaves lance- 

 oblong, pinnatifid, somewhat clasping, green on both sides ; segments irreg- 

 ularly lobed, ciliate and spinous ; involucre sub- globose ; scales appressed. 

 ovate-lanceolate, acuminate, spinous. Carduus pumilus NuU. 



Dry fields. N. Y. Mass, and Penn. July, Aug. .-Stem 12 feet high, 

 (sometimes much taller,) erect or subdecumbent. Heads very large. Flowers 

 pale purple. Pappus more than an inch long. Var. Hyslrix of Nuttall, has 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. Low Thistle. 



7. C. Nuttallii D. C. : stem much branched ; leaves sessile, smooth or 

 smoothish on both sides, pinnatifid ; lobes lanceolate, acuminate and with 

 the teeth spinous; involucre ovoid; scales lanceolate, appressed, with a 

 short somewhat reflexed spine at the apex, somewhat pubescent and viscid 

 upon the back. Carduus glaber NuU. Cnicus glaber ELI. 



Low grounds. N. J. Nutt. S. to Geor. %. Stem 4 5 feet high, slenderly 

 branched. Heads somewhat paniculate. Flowers pale purple. Allied to 

 C. muticum, and perhaps only a variety. Nuttall's Thistle. 



8. C. horridulum Mich. : stem simple or sparingly branched, arachnoid 

 when young; leaves lanceolate, partly clasping, pinnatifid, acutely divided, 

 very spinous, woolly beneath ; heads with a whorl of spinous bracts at 

 base ; involucre subglobose ; scales linear, acute, scarcely spinous. Car- 

 duus spinosissimus Walt. Cnicus horridulus Pursh. 



Sandy fields. IN. Y. to Flor. and Louis. July Sept. *2L Stem 23 feet 

 high, stout, hollow, lanuginous. Heads large, axillary and terminal, with 20 30 

 bracts at base, the outer of which have spines somewhat in pairs. Flowers dull 

 yellow, rarely pale purple. Yellow Thistle. 



9. C. Virginianum Mick. : stem slender, mostly simple, arachnoid ; leaves 

 sessile, lance-linear, revolute on the margin, distantly and spinosely serrate, 

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

 shortly mucronate, glutinous. Carduus Virginianus Willd. Cnicus Virgin- 

 ianus Pursh. 



Woods. Penn. ? to Geor. W. to Ken. July Sept. Q.St em 2^4 feet high, 

 covered with a white down, especially towards the summit. Head's small, 

 mostly solitary. Flowers purple. Virginian Thistle. 



57. LAPPA. Taurn. Burdock. 



(Said to l>e derived from the Celtic llap, &hand; because it lays hold of every- 

 thing near it. Tom) 



Heads many-flowered ; the flowers similar and perfect. 

 Corolla 5-cleft; tube 10-nerved. Involucre globose; scales 

 imbricate, coriaceous, with a long subulate inflexed point. Re- 

 ceptacle flat, covered with bristly chaff. Achenia oblong, com- 

 pressed, smooth, transversely rugose. Pappus of numerous 

 short distinct filiform rough bristles, caducous. 



