WOOTON AND STANDLEY FLOEA OF NEW MEXICO. 741 



KEY TO THE SPECIES. 



Annual 1. S. vulgaris. 



Perennials. 

 Heads discoid. 

 Heads small, 7 to 10 mm. high. 

 Glabrous; leaves linear to linear-oblanceolate, entire or 



nearly so 2. S. pudicus. 



Slightly tomentose; leaves cordate-ovate • to oblong- 

 lanceolate, coarsely toothed 3. S. sacramentanus. 



Heads large, 12 to 20 mm. high. 



Leaves long-villous on the midrib beneath; heads usually 



racemose 4. S. scopulinus. 



Leaves not long-villous; heads not racemose. 

 Plants more or less tomentose; leaves thick and fleshy. 5. S. chloranthus. 

 Plants glabrous; leaves thin. 

 Leaves coarsely and irregularly laciniate-serrate, 

 abruptly contracted at the base, mostly petio- 



late 6. S. bigelovii. 



Leaves finely and evenly serrate, attenuate to the 



very short petiole, or sessile 7. S. rushy i . 



Heads radiate. 



Plants densely viscid 8. S. parri/l. 



Plants not viscid. 

 Leaves or their divisions narrowly linear or linear-filiform. 



Plants permanently tomentose 9. S. filifolius. 



Plants glabrous. 

 Leaves entire, rarely with a pair of short filiform 



lobes at the base 10. S. spartioides. 



Leaves, except the uppermost, pinnately divided. 



Heads campanulate; bracts 12 to 15 11. S. riddellii. 



Heads cylindric or nearly so; bracts 8 to 10 12. S. multicapilatus. 



Leaves neither linear-filiform nor with linear-filiform 

 divisions. 

 Heads nodding. 



Plants low, not more than 10 cm. high; leaves obo- 



vate-orbicular, purplish 13. S. taraxacoides. 



Plants taller, 50 cm. high; leaves lanceolate or 



oblanceolate, not purplish 14. .9. amplectens. 



Heads not nodding. 

 Heads solitary. 

 Stems and leaves densely tomentose; stems with 



only a few much reduced leaves 15. S. actinella. 



Stems and usually the leaves glabrate; stems 



leafy 10. S. mogollonicua. 



Heads not solitary, except in depauperate sped 

 mens. 

 Plants equally Leafy throughout. 

 Leaves pinnatifid or pinnate. 

 Leaves pinnate, the terminal lobe orbicular 



or (-■eiiuorliii •ul.ir. obtusely toothed 17. S. tonguisorboides. 



Leaves pinnatifid, all the segments lanceolate 

 or narrower, with acme teeth. 

 Involucre 7 mm, high; leaves shallow ly 



pinnatind, with broad segments 18. S. ambroaioides. 



