1572 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM 



75. VERBESINA L. Sp. PI. 901. 1753. 

 Reference: Robinson & Greenman, Synopsis of the genus Verbesina, with 

 an analytical key to the species, Proc. Amer. Acad. 34: 534-566. 1899. 



Shrubs or herbs; leaves opposite or alternate; heads radiate or discoid, solitary 

 to numerous and panicled, usually yellow, sometimes orange or white; involucre 

 usually about 2-seriate, the phyllaries usually unequal and more or less herba- 

 ceous; rays usually fertile; achenes strongly compressed, 2-winged; pappus of 

 2 awns, very rarely wanting. 

 Rays white or none. 

 Rays none. 

 Stem winged; heads many-flowered. 



Leaves dentate, the larger usually sinuatelj^ lobed or pinnatifid; phyl- 

 laries ovate to linear-lanceolate 1. V. crocata. 



Leaves serrulate, ovate; phyllaries ovate to oblong 2. V. ovatifolia. 



Stem wingless; heads 7 to 9-flowered. 



Leaves lance-oblong 59. V. pauciflora. 



Leaves ovate or elliptic-ovate 60. V. oligantha. 



Rays present, white. 



Stem densely puberulous or subtomentose-pubescent. 



Stem winged nearly or quite to the inflorescence 56. V. turbacensis. 



Stem wingless. 



Leaves dentate; heads few; phyllaries broadly ovate. 



27. V. auriculata. 

 Leaves sinuate-lobed; heads numerous; phyllaries linear to oblanceolate. 



55. V. sublobata. 

 Stem glabrous or sparsely puberulous, usually glaucous or glaucescent. 



Internodes winged throughout 57. V. hypsela. 



Internodes and whole stem wingless 58. V. gigantoides. 



Rays present, yellow. 



Lamina of the rays 1 to 2.5 cm. long. 



Leaf bases decurrent, forming wings on the stem. 



Larger leaves sinuately 3-lobed; disk about 2 cm. thick 5, V. klattii. 



Leaves unlobed; disk much smaller. 



Leaves very finely and closely canescent beneath with appressed hairs. 



19. V. neriifolia. 

 Leaves rather loosely griseous- or canescent-tomentose or merely 

 puberulent beneath. 

 Leaves sessile. 



Leaves coarsely dentate 14. V. coahuilensis. 



Leaves subentire 21. V. petrophila. 



Leaves short-petioled. 



Leaves canescently pilose-tomentose beneath 20. V. gracilipes. 



Leaves green and merely puberulent beneath. _22. V. liebraannii. 

 Leaf bases not decurrent, the stem wingless. 



Leaves canescent-tomentose or finely canescent-sericeous beneath. 



Leaves sessile, amplexicaul 15. V. hypoleuca. 



Leaves petioled, not amplexicaul. 



Leaves densely pilose-tomentose beneath 20. V. gracilipes. 



Leaves not densely pilose-tomentose beneath. 



Leaves very finely and densely canescent-sericeous beneath; 



involucre 4 to 5 mm. high 18. V. hypoglauca. 



Leaves not densely canescent-sericeous beneath; involucre 5 to 

 8 mm. high. 

 Heads long-peduncled; leaf blades lanceolate to ovate, 2 to 

 7 cm. long 12. V. chihuahuensis. 



