GENUS 35. 



THISTLE FAMILY. 



15. Erigeron tenuis T. & G. Slender Rough 

 Fleabane. Fig. 4375. 



Erigeron tenuis T. & G. Fl. N. A. 2: 175. 1841. 



Annual or biennial, branched from the base and some- 

 times also above, strigose-pubescent ; stems slender, erect 

 or ascending, i high or less. Basal leaves obovate to 

 spatulate, i'-2i' long, 3"-6" wide, usually toothed; stem 

 leaves linear or linear-oblong, toothed or entire ; heads 

 several or solitary, slender-peduncled, 7"-io" broad ; in- 

 volucre 2"-3" high, its linear bracts glabrous or spar- 

 ingly pubescent ; rays white or purplish, numerous ; 

 pappus of ray-flowers and disk-flowers alike, of few 

 long bristles and short small scales. 



Moist prairies and plains. Missouri to Texas and Louis- 

 iana. April-May. 



16. Erigeron vernus (L.) T. & G. Early 

 Fleabane. Fig. 4376. 



Aster vernus L. Sp. PI. 876. 1753. 



E. nudicaulis Michx. Fl. Bor. Am. 2: 124. 1803. 



Erigeron vernus T. & G. Fl. N. A. 2: 176. 1841. 



Perennial by stolons and offsets ; stem slender, 

 simple or branched above, glabrous, or the 

 branches pubescent, i-2i high. Leaves mainly 

 in a basal rosette, glabrous, obovate, oval or spat- 

 ulate, obtuse, repand-denticulate or entire, 2'-^ 

 long, narrowed into margined petioles ; stem 

 leaves mostly reduced to subulate-lanceolate 

 scales, the lowest sometimes spatulate or oblong; 

 heads not numerous, corymbose, peduncled, about 

 5" broad ; involucre hemispheric, its bracts linear- 

 subulate; rays 20-30, white or pink, 2"-$" long; 

 pappus simple; achenes usually 4-nerved. 



In marshes and moist soil, Virginia to Florida and 

 Louisiana. April-May. 



17. Erigeron acris L. Blue or Bitter Flea- 

 bane. Fig. 4377. 



Erigeron acris L. Sp. PI. 863. 1753. 



Erigeron Droebachianus O. F. Mueller, Fl. Dan. pi. 874. 



1782. 

 Erigeron acris Droebachianus Blytt, Norg. Fl. i : 562. 



1861. 

 Erigeron acris debilis A. Gray, Syn. Fl. i : Part 2, 220. 



1884. 



Biennial or perennial; stem hirsute-pubescent or 

 glabrate, slender, simple, or branched above, 6'-2 

 high. Leaves pubescent or glabrous, entire, the 

 basal and lower ones spatulate, mostly obtuse, i'-3' 

 long, petioled, those of the stem mostly oblong or 

 oblanceolate, obtuse or acutish, sessile, shorter; 

 heads several or numerous, racemose or paniculate, 

 peduncled, 5"-6" broad; involucre hemispheric, its 

 bracts linear, hirsute to glabrous ; rays numerous, 

 purple, equalling or slightly exceeding the brownish 

 pappus ; tubular pistillate flowers filiform, numer- 

 ous; pappus simple or nearly so, copious. 



Labrador to Alaska, Maine, Ontario, south in the 

 Rocky Mountains to Colorado and Utah. Also in Eu- 

 rope and Asia. Races differ in size, pubescence and 

 length of rays. July-Aug. 



