1160 CARDUACEAE 



acuminate, sharply and rather finely serrate : heads rather crowded : involucres 6-7 mm. 

 long, 4-5 mm. wide ; bracts pubescent, sometimes hoary, acute or with short keel-like 

 acuminations, the tips erect or slightly spreading : achenes pubescent : pappus purple. 

 On plains or prairies, Missouri and Kansas, south to Texas. 



14. Vernonia Drummdndii Shuttlw. Foliage tomentose. Stems! -2m. tall, branch- 

 ing above : leaves numerous ; blades elliptic to elliptic-lanceolate or linear-elliptic, 1-3 

 dm. long, acute or short-acuminate, sharply serrate : corymbs usually 1-4 dm. broad : 

 peduncles barely enlarged upward : involucres rounded at the base, 8-12*mm. high ; bracts 

 ovate to oblong, acute or apiculate : achenes 4-5 mm. long, with smooth and glabrous ribs : 

 pappus tinged with purple. 



On prairies, Illinois to Kansas, Alabama and Texas. 



15. Vernonia Guadahip6nsis Heller. Foliage light green, minutely pubescent. 

 Stems 3-15 dm. tall, corymbosely branched above, prominently ridged : leaves numerous ; 

 blades linear or nearly so, 8-15 cm. long, 4-12 mm. wide, attenuate, undulate or remotely 

 denticulate : involucres carnpanulate, 6-8 mm. high, 5-6 mm. broad ; bracts abruptly 

 pointed, hoary, with erect or slightly spreading tips : achenes 3.5-4 mm. long, prominently 

 ribbed, slightly glandular : pappus purple. 



In limestone river bottoms, Texas. 



16. Vernonia fasciculata Michx. Foliage glabrous, or pubescent above. Stems 

 0.5-2 m. tall, simple below the inflorescence : leaves numerous ; blades linear to linear- 

 lanceolate, 5-15 cm. long, attenuate, sharply serrate : corymbs 5-15 cm. broad : peduncles 

 slightly enlarged above : involucres campanulate at maturity, 5-6 mm. high, about 5 mm. 

 broad ; bracts firm, oblong-ovate to nearly oval, -acute or acutish, appressed : achenes 3 

 mm. long, with smooth ribs : pappus purple. 



On plains and prairies, Ohio to South Dakota, south to Texas. 



17. Vernonia tenuifolia Small. Foliage thinly pubescent. Stems 0.5-1 m. tall, 

 branching above : leaves numerous ; blades linear or nearly so, 0.5-1.5 dm. long, acute, 

 serrate, minutely punctate : corymbs 5-10 cm. broad, with rather few heads : peduncles 

 slightly enlarged upward : involucres campanulate, 8-10 mm. high, purple ; bracts ovate 

 to oblong, erect, acute or mucronate : achenes about 4 mm. long, with smooth and gla- 

 brous ribs : pappus straw-colored or tinged with purple. 



In dry soil, southern and western Texas. 



18. Vernonia marginata (Torr. ) Britton. Foliage pubescent above. Stems 1-1.5 

 m. tall, corymbosely branched above ; leaves relatively few ; blades linear, 5-15 cm. long, 

 or longer near the base of the stem, acute, entire : peduncles slightly enlarged above : in- 

 volucres cylindric-campanulate, about 1 cm. high ; bracts ovate-lanceolate to oblong-lan- 

 ceolate, acuminate, margined, with barely spreading tips: achenes 3-3.5 mm. long. 



In dry soil, Nebraska to Texas and New Mexico. 



19. Vernonia Lettermanii Engelm. Foliage glabrous or nearly so. Stems 0.5-1.5 

 m. tall, fastigiately branched above : leaves numerous and crowded ; blades narrowly 

 linear, 5-12 cm. long, acute, entire, each with a conspicuous midrib : peduncles angled, 

 slightly enlarged upward : involucres cylindricor campanulate at maturity, 6-7 mm. high, 

 narrowed at the base ; bracts lanceolate to linear-oblong, acute or somewhat acuminate : 

 achenes 4 mm. long, glandular, slightly rough on the ribs : pappus purplish. 



In sandy soil, Arkansas. 



20. Vernonia angustifolia Michx. Foliage nearly glabrous. Stems 0.5-1 m. tall, 

 often widely branched above : leaves numerous ; blades linear, usually narrowly so, 5-15 

 cm. long, acute, revolute : peduncles variable, slightly enlarged near the top, 1-2 cm. long, 

 or some heads sessile : involucres turbinate or turbinate-campanulate, 5-6 mm. high, acute 

 or somewhat rounded at the base ; bracts lanceolate to oblong, acute or apiculate, with more 

 or less spreading tips : achenes 2 mm. long, with scabrous ribs : pappus purplish. 



In sand, Georgia and Florida to Mississippi. 



21. Vernonia Texana (A. Gray) Small. Foliage glabrate. Stems wand-like, 4-12 

 dm. tall, branching above : leaves relatively few ; blades oblong-oblanceolate to linear- 

 lanceolate or linear, 5-20 cm. long, acute or acuminate, at least the lower ones remotely 

 toothed : corymbs with slender branches : peduncles variable, 0.5-5 cm. long, barely 

 enlarged above : involucres turbinate-campanulate, 5-6 mm. high ; bracts ovate to oblong, 

 apiculate : achenes 3 mm. long, with sparingly barbed ribs : pappus pale purple. 



In sandy soil, Florida to Texas and^Arkansas. 



22. Vernonia Blodg6ttii Small. Foliage glabrous below the inflorescence. Stems 

 often branched near the base, 2-5 dm. long, narrowly corymbose above: leaves ^ mostly 

 near the base of the stem ; blades oblong to linear, 2-4.5 cm. long, obtuse or acutish, en- 



