1158 CARDUACEAE 



Outer bracts of the involucre merely acuminate. 4. V. glauca. 



Leaf-blades decidedly scabrous above. 



Leaf-blades coarsely toothed or crisped : bracts of the involucre with 



soft tips. 5. V. pulchella. 



Leaf-blades entire or minutely toothed : bracts of the involucre rigid. 6. V. scaberrima. 

 b. Bracts of the involucre obtuse to acuminate. 



Leaves with blades of various types, but not linear. 

 Leaf-blades glabrous or nearly so on both sides. 



Involucres fully as broad as high. 7. V. flaccid-tfolia. 



Involucres much or manifestly higher than broad. 

 Bracts of the involucre obtuse or merely acute. 



Involucres hemispheric-campanulate, rounded at the base; 



bracts appressed at maturity. 

 Involucres few-flowered, about 3 mm. high ; inner bracts 



narrowly oblong or linear-oblong. 8. F. oligantha. 



Involucres many-flowered, 4 mm. to almost 5 mm. high ; inner 



bracts broadly oblong. 9. V. maxima. 



Involucres cylindric, narrowed at the base; bracts loosely 



spreading at maturity. 10. V. gigantea. 



Bracts of the involucre, or some o" them, acuminate. 11. V. ovalifolia. 



Leaf-blades manifestly pubescent benea-u, often densely so. 

 Involucres 4-6 mm. high. 



Bracts of the involucre with recurved tips. 12. V. Baldwinii. 



Bracts of the involucre with erect or slightly spreading tips. 13. V. interior. 



Involucres 8-12 mm. high. 14. V. Drummondii. 



Leaves with blades of a linear type. 



Stems, lower surfaces of leaf-blades and involucres glabrous or some- 

 what pubescent, but not white- woolly. 

 Leaf-blades smooth above. 



Lower surfaces of the leaf-blades, at least the midnerve, pubescent. 15. V. Guadalupensis. 

 Lower surfaces of the leaf-blades glabrous. 



Leaves neither exceedingly numerous not crowded. 

 Bracts of the involucres obtuse or merely acute. 



Involucres about 5 mm. broad. 16. V. fasciculata. 



Involucres about 8 mm. broad. 17. V. tenuifolia. 



Bracts of the involucres acuminate. 18. V. marginata. 



Leaves excedingly numerous and crowded. 19. V. Lettermanii. 



Leaf-blades scabrous above. 



Bracts of the involucres with slender spreading tips. 20. V. angustifolia. 



Bracts of the involucres with merely acute erect or appressed tips. 



Leaf-blades, at least the lower ones, remotely toothed. 21. V. Texana. 



Leaf-blades entire. 22. V. Blodgettii. 



Stems, lower leaf-surfaces and involucres conspicuously white-woolly. 23. V. Lindheimeri. 

 B. Leaves mainly or all basal. 24. V. oligophylla. 



1. Vernonia crinita Raf. Foliage glabrous or somewhat pubescent. Stems 1-4 m. 

 tall, branched above : leaves numerous ; blades linear or linear-lanceolate, 1-3 dm. long, 

 attenuate at both ends, finely serrate : corymbs 1-2 dm. broad : peduncles club-shaped : in- 

 volucres hemispheric, becoming 1.5 cm. high and fully 1.5 cm. broad ; bracts greenish, 

 prolonged into filiform tips, the outer with little or no body : achenes 5 mm. long, upwardly 

 barbed on the angles : pappus purplish. 



On plains and banks of streams, Missouri to Kansas and Texas. 



2. Vernonia Noveborac6nsis ( L. ) Willd. Foliage nearly glabrous, or pubescent. 

 Stems 1-3 m. tall, branching above : leaves rather numerous ; blades linear-lanceolate or 

 elliptic-lanceolate, 1-2 dm. long, acuminate, finely serrate or nearly entire, often minutely 

 pubescent beneath : corymbs 1-3 dm. broad, commonly irregular : peduncles angled, 

 slightly enlarged above : involucres hemispheric, about 5 mm. high ; bracts purple, ovate 

 or ovate-lanceolate, prolonged into filiform tips : achenes 4 mm. long, upwardly barbed 

 along the sharp angles : pappus purple. 



In thickets and open places, Massachusetts to Minnesota, Georgia and Missouri. 



3. Vernonia tomentosa (Walt. ) Ell. Foliage rather thinly tomentose. Stems 1-2 

 m. tall, simple below : leaves rather numerous ; blades elliptic to narrowly elliptic-lanceo- 

 late, 1-2 dm. long, acute or acuminate, sharply serrate : corymbs 1-3 dm. broad : peduncles 

 slightly, if at all, enlarged above : involucres hemispheric, about 6 mm. high ; bracts 

 lanceolate to oblong-lanceolate, prolonged into subulate or filiform tips : achenes 3 mm. 

 long, sometimes nearly glabrous : pappus straw-colored. 



On hillsides, New Jersey and Pennsylvania to North Carolina. 



4. Vernonia glauca (L. ) Britton. Foliage thinly tomentose. Stems 1-2 m. tall, 

 often widely branched above : leaves numerous ; blades linear-lanceolate to elliptic or 

 elliptic-oblanceolate, acute or short-acuminate, finely serrate : corymbs 1-3 dm. broad : 

 peduncles angled or winged, barely enlarged above : involucres hemispheric, about 5 mm. 

 high ; bracts lanceolate to nearly oblong, purple, the outer ones merely acuminate : achenes 

 2-3 mm. long, with the sharp ribs barbed : pappus straw-colored. 



On river banks, Virginia to Georgia. 



5. Vernonia pulchella Small. Foliage hirsute. Stems solitary or clustered, 3-10 

 dm. tall, branched above : leaves firm ; blades oblong-lanceolate or oblong to nearly linear- 



