Aster COMPOSITAE 



933 



Bracts mostly less than 7 mm long. 



Leaves linear to linear-lanceolate; large plants with long, 



wide-spreading branches 25. A. pilosus. 



Leaves lanceolate to oblong-lanceolate; inflorescence not as 



large and spreading 25a. A. pilosus var. platyphyllus. 



Stems glabrous or pubescent in lines. 



Plants large and bushy 25b. A. pilosus var. clemotus. 



Plants simple, small, usually about 3-6 dm high, branches short, 

 heads few. (A northern form, see excluded species no. 632, 



p. 1098) a pilosus var. Pringlei. 



b. Involucral bracts without mucronate tips. 



Bracts with green tips and midribs; leaves lanceolate to ovate- 

 lanceolate, serrate in the middle; inflorescence paniculate, heads 

 mostly racemose; corolla tube campanulate. 

 Inner bracts of the involucre 3.2-4.6 mm long; lobes of the disk- 

 corollas (0.8) 1-1.2 mm long; heads racemose on long, spreading 



branches 26. A. missowriensis. 



Inner bracts 2.8-3 mm long; lobes of the disk-corollas 0.7-1 mm 

 long; plant more strict, with a more abundant small, ascending 



rameal leaves and smaller, more densely racemose heads 



26a. A. missouriensis var. thyrsoides. 



Bracts without green tips or the midrib only somewhat green; leaves 

 lanceolate to elliptic, much larger, entire; inflorescence composed 

 mostly of compound corymbs, generally flat-topped; corolla tube 



funnel-shaped 2 7. A. umbellatus. 



a. Leaves glabrous beneath or pubescent only on the midrib. 



Plants with a flat-topped inflorescence, composed generally of compound 

 corymbs; leaves mostly 1-3 cm wide, 5-12 cm long, margins entire, 

 ultimate areolae conspicuous, very small, usually less than 0.5 mm 

 in diameter; pappus-bristles in 2 series, the outer very short 



27. A. umbellatus. 



Plants not as above. 



Plants branched at the top, with stiff, linear leaves, mostly 2-3.5 mm 

 wide, 2-4 cm long; flowers few; involucres about 7 mm high, in 

 several series, thick, mostly obtuse or merely acute; rays violet. 



20. A. linariifolius. 



Plants not as above. 



Involucral bracts subequal, mostly 8-10 mm long, in 1 or 2 rows. 

 Annual; pappus much longer than the disk flowers. (See excluded 



species no. 626, p. 1097) a. angustus. 



Perennial; pappus about as long as the disk flowers; plant glabrous 



or nearly so; leaves lanceolate to linear-lanceolate 



14. A. longifolius. 



Involucral bracts not subequal, less than 8 mm long, usually in 3 or 4 

 series. 



Plants with a white, flat-topped inflorescence; involucre less than 5 

 mm high, the bracts fleshy and closely appressed; leaves linear- 

 lanceolate or linear, with 3 longitudinal veins usually visible; 

 plants of the dunes about Lake Michigan. . .28. A. ptarmicoides. 

 Plants not as above. 

 Heads in more or less 1-sided racemes. 



Plants with (9) 11-12 (14) rays; leaves lanceolate to elliptic- 

 lanceolate or oval-lanceolate; heads mostly 7-10 mm wide, 

 usually on short branchlets 1-10 mm long, the branchlets 

 mostly shorter than the subtending leaves; involucre 4-5.5 

 mm long; corolla of disk flowers goblet-shaped, its lobes 

 1-1.6 mm long; lobes 50%-75% of the total length of the 

 limb. 



