256 American Midland Naturalist Monograph No. 2 



27. Heads smaller, 7-14 mm. in diameter; rays 

 2-6 mm. long, lavender or white. 

 30. Heads in a narrow or open panicle. 



3 1 . Leaves finely pubescent beneath, pu- 

 berulent above, oblanceolate, or 

 lanceolate, frequently serrate; road- 

 sides, fields, river banks, common 

 throughout 111. Sept. -Oct. [A. 

 missouriensis of Britt., not A. niis- 



surtenus (Nutt.) Ktze} 



A. pantotrichus Blake 



3 1 . Leaves glabrous beneath, more or 



less scabrous above, entire or spar- 

 ingly serrate; moist woods, local. 

 Sept. -Oct. [A. tradescanti ex p. of 

 auth.j A. interior Wieg. 



30. Heads unilaterally racemose. 



32. Leaves lanceolate or oblanceolate, 



serrate; involucres 4-5 mm. high; 

 rays 10-12, white or bluish; woods, 



common. Sept. -Oct 



A. latertflorus (L.) Britt. 



32. Leaves linear, denticulate or entire; 

 involucres 3-4 mm. high; rays 15- 

 25, white; fields, woods, and road- 

 sides, local. Sept. -Oct 



A. vimineus Lam. 



21. Involucres 8-10 mm. high; bracts linear-lanceolate, 

 keeled, appressed, imbricate in 4-5 series; rays 10-15, 

 violet or rarely white, 8-10 mm. long; leaves numer- 

 ous, linear, entire, sessile, 1 -nerved, rigid, usually 

 ciliolate; sandy soil in woods in the n. half of the 

 state. Sept.-Oct. [lonactis linariijolius (L.) Greene] 

 A. linariijoliits L. 



19. Heads in flat-topped corymbs; rays white or whitish; involu- 

 cres 4-5 mm. high. 



33. Leaves rigid, Hnear-lanceolate, acute; rays about 8 mm. 

 long; achencs glabrous; pappus simple; sandy soil, Lake, 

 Mchlenry, Du Page, Cook, and Kankakee counties; also 

 Menard Co., Hall. Aug. -Sept. [A. ptarmkoides var. lii- 

 tcscens (Lindl.) Gray; Unamia lutacens (Lindl.) 

 Rydb.] A. ptarmicotdci (Nees) T. & G. 



33. Leaves lanceolate, acuminate, not rigid; rays 4-6 mm. long; 

 achenes slightly pubescent; pappus double; moist ground 

 in the n. half of the state, local. Aug. -Oct. [Docllingeria 



