COMPOSITiE, 203 



Low grounds. Can. to Louis. W. to Texas. Aug., Sept. % or @. — Stem 

 'i — 5 feet high, striate and angular. Heads middle-sized, terminal. Flowers 

 purj^le. Awnless Thistle. 



6. C. puviilum 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 Nutt. 



Dry fields. N. Y. Mass. and Penn, July, Aug. ^.—Stem 1—2 feet high, 

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

 pale purple. Pappus more than an inch long. Var. Hystrix of Nuttall, has the 

 stem simple, l-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 Nutt. Cnicus glaber Ell. 



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. Nuttairs 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 spiiwsissimus Walt. Cnicus horridulus Pursh. 



Sandy fields. N. Y. to Flor. and Louis. July— Sept. %.—Stem 2—3 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 Mich. : 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. C^iicus Virgin- 

 ianus Pursh. 



Woods. Penn. ? to Geor. W. to Ken. July— Sept. %.—Stem 2—4 feet high, 

 covered with a white down, especially towards the summit. Heads small, 

 mostly solitary. Flowers purple. Virginian Thistle. 



57. LAPPA. Tlywrn.— Burdock. 



(Said to l3e derived from the Celtic llap, a hand ; because it lays hold of every- 

 thing near it. Torr.) 



Heads many-flowered ; the flowers similar and perfect. 

 Corolla 5-cleft ; tiibe 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. 



