WOOTON AND STANDLEY—FLORA OF NEW 
KEY TO THE SPECIES. 
Annual............-. 02-222 ee eee ee eee teens 
Perennials. 
Heads discoid. 
Heads small, 7 to 10 mm. high. 
Glabrous; leaves linear to linear-oblanceolate, entire or 
nearly S0.......2.2-2220- 0-222 ee eee eee eee eee eee 2. 
Slightly tomentose; leaves cordate-ovate to oblong- 
lanceolate, coarsely toothed...........------------ 3. 
Heads large, 12 to 20 mm. high. 
Leaves long-villous on the midrib beneath; heads usually 
TACCMOSC....-- eee ewe ee ee ee ee eee eee eee eee 4, 
Leaves not long-villous; heads not racemose, 
Plants more or less tomentose; leaves thick and fleshy. 5. 
Plants glabrous; leaves thin. 
Leaves coarsely and irregularly laciniate-serrate, 
abruptly contracted at the base, mostly petio- 
Leaves finely and evenly serrate, attenuate to the 
very short petiole, or sessile...........-..------ 7. 
Heads radiate. 
Plants densely viscid........-.--...-----+---+-++++--+-+---- 8. 
Plants not viscid. 
Leaves or their divisions narrowly linear or linear-filiform. 
Plants permanently tomentose.............---------- 9. 
Plants glabrous. 
Leaves entire, rarely with a pair of short filiform 
lobes at the base.............----------------- 10. 
Leaves, except the uppermost, pinnately divided. 
Heads-campanulate; bracts 12 to 15.....--.------- 11. 
Heads cylindric or nearly so; bracts 8 to 10.....-.- 12. 
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. 
Plants taller, 50 cm. high; leaves lanceolate or 
oblanceolate, not purplish................------ 14. 
Heads not nodding. 
Heads solitary. 
Stems and leaves densely tomentose; stems with 
only a few much reduced leaves. ......------ 15. 
Stems and usually the leaves glabrate; stems 
leafy. ..--------- 22-22-02 e ee eee eee ee eee 16. 
Heads not solitary, except in depauperate speci- 
mens. 
Plants equally leafy throughout. 
Leaves pinnatifid or pinnate. 
Leaves pinnate, the terminal lobe orbicular 
or semiorbicular, obtusely toothed. ....... 17. 
Leaves pinnatifid, all the segments lanceolate 
or narrower, with acute teeth. 
Involucre 7 mm. high; leaves shallowly 
pinnatifid, with broad segments. -..... 18. 
MEXICO. 
S, 
741 
1. S. vulgaris. 
. pudicus. 
. sacramentanus. 
scopulinus. 
S. chloranthus. 
. bigelovir. 
. rusbyt. 
. parryi. 
S. filifolius. 
8, 
S. 
. multicapitatus. 
spartiordes. 
riddellir. 
. taraxacoides. 
. amplectens. 
. actinella, 
. mogollonicus. 
. sanguisorboides. 
. ambrosioides., 
