COMPOSITAE (COMPOSITE FAMILY) 



577 



14. S. glaucescens. 

 17. S. perplexus. 



18. S. atratus. 



19. S. altus. 



20. S. canus. 



21. S. werneriaefolius. 



22. S. perennans. 



23. S. petrocallis. 



20. S. canus. 



24. S. Nclsonii. 



25. S. Fendleri. 



Teeth of leaves callous-tipped 

 Teeth of leaves not calloused 

 Permanently tomentose or hoary. 



Stems tall (4 dm. or more); leaves denticulate 



or dentate. 



Stems leafy to the summit 

 Stems subnaked above 

 Stems lower (less than 4 dm.); at least the 'lower 



leaves entire 

 Stems scapose, the leaves mostly rosulate on the 



crowns. 



Leaves elliptic to linear-oblanceolate, mostly entire 

 Leaves linear-spatulate 

 Leaves elliptic ...'.. 

 Leaves reniform, orbicular or obovate, toothed at 



least at the apex .... 

 Leaves, or some of them pinnate or pinnatifid. 

 Leaves more or less reduced upward. 



Stem and leaves more or less floccose, tardily glabrate 

 Basal leaves entire, white-tomentose 

 Basal leaves, at least some of them, toothed or pinnati- 

 fid. 



Basal leaves only dentate or crenate. 

 Plants more or less tufted 

 Plants usually solitary (not tufted) . '. 

 Basal leaves, or some of them, more or less pinnatifid'. 

 At least some of the tomentum persisting. 



Some of the basal leaves simple and serrate or, 

 if pinnate, the terminal lobe much the larg- 

 est 



All of the basal leaves pinnately toothed 



All of the tomentum wanting at maturity 



Stems and leaves glabrous, or slightly floccose when 



young only. 

 Rays present. 



Heads several to many. 

 Leaves fleshy-thickened. 



Basal leaves tapering gradually to the petiole, 



variously toothed ..... 



Basal leaves abruptly contracted into the petiole, 



some of them deeply toothed or pinnately 



lobed. 



Upper leaves sessile by an enlarged base 

 Upper leaves not dilated at base . 

 Leaves thin ........ 



Heads solitary (rarely two) 



Basal leaves cordate, oval, or obovate. 

 Basal leaves larger than the others 

 Basal leaves small and soon deciduous . 

 Basal leaves obovate to oblanceolate, never cor- 

 date. 



Stem leaves closely pinnatifid . . . 34. S. Balsamitae. 

 Stem leaves with few short broad pinnae . 35. S. mutabilis. 



Rays wanting 36. S. discoideus. 



Leaves equable in size and distribution. 



Leaves pinnately or bipinnately toothed . . .37. S. eremophilus. 

 Leaves with few to many linear-filiform lobes. 



Plants more or less permanently tomentose . . . 38. S. filifolius. 

 Plants glabrous or soon glabrate. 



Most of the leaves pinnately divided . . 39. S. Riddellii. 

 Most of the leaves linear-entire . . . . 40. S. spartioides. 

 Annual, often a weed 41. S. vulgaris. 



1. Senecio Bigelovii Gray, Pacif. R. R. Rep. 4: 111. 1857. Robust, 4-8 

 dm. high, leafy nearly to the racemiform or simply paniculate inflorescence, at 

 length glabrate: leaves elongated-oblong to lanceolate, denticulate or dentate, 

 acute or acuminate; the radical and lower cauline 1-2 dm. long, abrupt at 

 base and naked-petioled, or tapering into a winged petiole or partly clasping 

 base; the upper cauline lanceolate with partly clasping base: heads rayless, 

 nodding, in small plants few or solitary. S. contristatus Greene, PI. Baker. 

 3: 24. 1901; S. chloranthus Greene, Pitt. 4: 118. 1900. In the mountains of 

 southern Colorado, and in adjacent New Mexico and Arizona. 



la. Senecio Bigelovii Hallii Gray, Proc. Phila. Acad. 67. 1863. Leaves 

 almost all lanceolate, more or less woolly-pubescent, hairs articulated; cau- 

 line leaves all sessile or the lowest contracted into a winged petiole: heads 



ROCKY MT. EOT. 37 



26. S. plattensis. 

 25. S. Fendleri. 



27. S. uintahensis. 



28. S. Rydbergii. 



29. S. crocatus. 



30. S. cymbalarioides. 

 27. S. uintahensis. 



31. S. subnudus. 



32. S. pseudaureus. 



33. S. longipetiolatus. 



