COMPOSITAE. 967 



flowers yellow, tubular, perfect, their corollas mostly 5-lobed. Anthers obtuse and 

 entire at the base. Style-branches more or less flattened, their appendages short, 

 mostly rounded or obtuse. Achenes flattened, usually 2-nerved. Pappus-bristles 

 fragile, slender, scabrous or denticulate, in I series, or often an additional outer 

 shorter series. [Greek, early-old, alluding to the early hoary pappus.] A genus of 

 some 130 species, of wide distribution. In addition to the following, about 60 

 others occur in southern and western N. Am. 



* Rays long, narrow, usually equalling or longer than the diameter of the disk. 

 t Stem 2-25 cm. high, simple, leafy; head solitary; involucre woolly. 



i. . uniflorus. 

 1 1 Stem 1-9 dm. high, leafy, usually branched; involucre hirsute or glabrous. 



i. Roots perennial, thick and woody. 



Heads 25-50 mm. broad ; leaves lanceolate, ovate, oblong, or spatulate. 

 Rays violet or purple; stem-leaves ovate, lanceolate, or oblong. 



Stem-leaves linear-lanceolate, the upper much smaller. 2. E. asper 

 Stem-leaves ovate-lanceolate, the upper little smaller. 3. E. subtrinervis. 

 Rays mostly white; stem-leaves linear or linear-oblong. 4. E. caespitosus. 



Heads 12-25 rnm. broad; leaves linear. 



Plants hirsute or canescent; pappus double; western species. 



Stem hirsute; achenes pubescent ; flowers white. 5. E. pumilus. 



Stem appressed-canescent ; achenes glabrous; flowers purple or white. 



6. E. can us. 



Plant nearly glabrous; pappus simple; northern. 7. E, hyssopifolius. 



a. Perennial by decumbent rooting stems or stolons. 



8. E. Magellan's. 



3. Roots annual or biennial, fibrous ; plants often perennial by offsets. 

 Heads 25-37 mm. broad, few-, stem simple ; eastern. 9. E. pulchellus. 



Heads 12-25 mm. broad, numerous; stem branched. 

 Rays 100-150, narrow, mostly purple or violet. 



Pappus simple; plant erect, corymbosely branched. 10. E. Philadelphicus. 



Pappus double; plant diffusely branched, western. n. E. divergens. 



Rays much less numerous, purplish or white. 



Plants 1.5-3 dm. high, diffuse, western; pappus simple. 12. E. Bellidiastrum. 

 Plants 3-10 dm. high, erect, corymbosely branched; pappus double. 



Stem-leaves lanceolate, nearly all sharply serrate. 13. E. annuus. 

 Stem-leaves linear-lanceolate or oblong, nearly all entire. 



14. E. ramosus. 

 fft Stem leafless or nearly so ; heads 12 mm. broad, corymbose. 



15. E. vernus. 



* * Rays inconspicuous or short; a row of tubular pistillate flowers inside the row of 



rays. 16. E. acris. 



1. Erigeron uniflorus L. ARCTIC ERIGERON. (I. F. f. 3811.) Perennial 

 by short branching rootstocks ; stems slender, single or tufted, more or less pubes- 

 cent, simple, erect. Basal leaves petioled, spatulate, obtuse, entire, 2-5 cm. long; 

 stem-leaves sessile, lanceolate or linear-lanceolate, entire; head solitary, pedun- 

 cled, 12-25 mm. broad; rays about 100, purple or purplish, 4-8 mm. long; bracts 

 linear-lanceolate, acute, copiously woolly ; pappus simple. Lab. and arctic Am. 

 to Alaska. Rocky Mts. specimens referred to this species belong to E. simplex. 

 Also in Europe. Summer. 



2. Erigeron asper Nutt. ROUGH ERIGERON. (I. F. f. 3812.) Stem sim- 

 ple, or branched above, more or less pubescent, sometimes hirsute, 1.5-6 dm. high. 

 Leaves glabrous, pubescent or ciliate, entire, the basal ones spatulate, obtuse, 

 5-10 cm. long, 6-25 mm. wide, narrowed into margined petioles; stem-leaves 

 oblong-lanceolate or linear-lanceolate, obtuse or acute, the upper smaller; heads 

 several or solitary, slender-peduncled, 2-5 cm. broad; bracts linear, acute, hirsute 

 or pubescent; rays 100-150, very narrow, violet, purple, or nearly white, 8 14 mm. 

 long; pappus double, the outer row of bristles much shorter than the inner. In 

 dry soil, Minn, to Neb., west to the N. W. Terr., Utah and N. Mex. June-Sept. 



3. Erigeron subtrinervis Ryclberg. THREE-NERVED FLEABANE. (I. F. f. 

 3813.) Similar to the preceding species, finely pubescent. Stems leafy to the 

 inflorescence; leaves entire, thin, the basal and lower ones oblanceolate to oblong, 

 obtuse or acute, petioled, the upper lanceolate or ovate-lanceolate, sessile or some- 

 what clasping, acute, rather distinctly 3-nerved; heads 25-37 mm. broad, corym- 

 bose, or rarely solitary; rays numerous, blue to pink; pappus double, the outer 

 bristles very short. S. Dak. to Neb. and Utah. 



