1622 CONTEIBUTIONS FROM THE NATIONAL HERBAEIUM 



Leaves lance-attenuate and entire to ovate and irregularly laciniate; upper 

 leaves sessile and auriculate. 



Leaves glabrous 4. S. lemmoni. 



Leaves white-tomentose beneath 5. S. alvarazensis. 



Leaves linear and entire to pinnately parted with narrow remote lateral 

 divisions; upper leaves not auriculate. 

 Involucral bracts usually 21. 



Heads 1 to 1.5 cm. high; bracteoles conspicuous, two-thirds as long as 



the involucre 6. S. douglasii. 



Heads 1 to 1.2 cm. high; bracteoles inconspicuous, less than half as long 



as the involucre 7. S. filif olius. 



Involucral bracts usually 13 8. S. flaccidus. 



Leaves narrowly lanceolate, entire to sparingly dentate, never pinnately 

 parted. 

 LTpper leaves auriculate. 



Involucral bracts 21 9. S. picridis. 



Involucral bracts 13 10. S. carnerensis. 



Upper leaves not auriculate 11. S. stoechadiformis. 



Inflorescence few-headed; heads frequently solitary. 



Stems procumbent 12. S. procumbens. 



Stems erect 13. S. calcarius. 



III. FRUTICOSI. 



Leaves lanceolate. 



Calyculate bracteoles broad, conspicuous 14. S. cinerarioides . 



Calyculate bracteoles narrow, inconspicuous. 

 Plants more or less tomentose. 



Leaves sessile or nearlj' so, sparingly tomentose beneath. . 15. S. argutus. 

 Leaves distinctly pctiolate, densely and permanently tomentose beneath. 



16. S. thomasii. 



Plants glabrous 17. S. salignus. 



Leaves oblong-ovate to ovate-rotund. 



Leaves cuneate at the base 18. S. schaff neri. 



Leaves cordate at the base. 



Involucre densely tomentose 19. S. barba-johannis. 



Involucre glabrous or nearly so. 



Stem and branches densely hirsute-tomentose 20. S. hirsuticaulis. 



Stem and branches floccose-tomentose to glabrous. 



21. S. aschenbornianus. 



IV. PALMATINERVII. 

 Inflorescence densely white-tomentose to glabrous, in no sense glandular. 

 Heads numerous, small or medium-sized, 6 to 12 mm. high. 

 Upper leaf surface closely and conspicuously reticulate-veined. 

 Involucre tomentose. 



Heads radiate 22. S. roldana. 



Heads discoid 23. S. jaliscanus. 



Involucre glabrous. 



Lower leaf surface tomentose 24. S. hartwegi. 



Lower leaf surface glabrous 25. S. seemannii 



Upper leaf surface not closely and conspicuously reticulate-veined. 



Heads disposed in glomerules 26. S. robinsonianus. 



Heads not disposed in glomerules. 



Petioles not denselv lanate .-27. S. albonervius. 



