Aster COMPOSITAE 931 



thick, glossy, slightly revolute with strongly involute, 



indurated tips, covered above more or less with 



short, stout, forward-pointing hairs, especially near 



the margins and at the apical end; flowers in dense, 



racemose clusters toward the ends of the branches; 



rays light lavender. 



Leaves of the branches linear or linear-lanceolate or 



narrowly elliptic-lanceolate, very acute. 



Leaves of stem and branches lanceolate to narrowly 



elliptic-lanceolate, those of the primary branches 



6-10 times as long as broad. . . .16. A. praealtus. 



Leaves of the stem and branches linear or nearly so, 



those of the primary branches about 11 times as 



long as broad. .16a. A. praealtus var. angustior. 



Leaves of the branches, at least the ultimate, broadly 



elliptic-lanceolate or oval, often obtuse 



16b. A. praealtus var. subasper. 



Veinlets of the under surface of the blades not con- 

 spicuous, the areas enclosed by them longer than 

 broad; stem and branches not very leafy; leaves 

 dark green, thinner than those of the preceding, 

 usually flat and not involute at the tip, not glossy, 

 more or less pubescent above but the hairs not as 

 stout as those in the preceding species; heads 

 usually not clustered, mostly white, rarely colored. 

 Involucre 5-7 mm high, hemispheric; inflorescence sub- 

 corymbose, not crowded; heads large, spread of 

 rays 15-25 mm, rays commonly 30 or more; lobes 

 of disk flowers short, about 25% of the total 

 length of the limb; leaves always linear; plants 



usually of a marsh habitat 17. A. junceus. 



Involucre 3-5.5 mm high, turbinate; inflorescence pani- 

 culate, heads numerous, of medium size or smaller, 

 spread of rays 10-20 mm; rays usually less than 

 30; lobes of disk flowers moderately deep, 40%- 

 50% of the total length of the limb; leaves linear 

 to lanceolate; plants of moist or dry habitats. 

 Heads of medium size, spread of rays 12-20 mm; in- 

 volucre (4) 4.5-5.5 mm high; rays 6-11 mm long. 

 Leaves linear, 12 times as long as broad or longer. 



18. A. panicalatus. 



Leaves lanceolate, less than 12 times as long as 



broad 18a. A. paniculatus var. simplex. 



Heads smaller, spread of rays 10-16 mm; involucre 



3-4 (4.5) mm high; rays 4.4-8.5 mm long 



19. A. interior. 



D. Stems pubescent more or less over the entire surface, not in lines. 



Leaves glabrous above and beneath, margins scabrous, narrow, 



mostly 2-3.5 mm wide and 2-4 cm long; flowers usually few; 



involucre about 7 mm high; bracts thick, mostly obtuse or 



merely acute; rays violet 20. A. linariifolius. 



Leaves pubescent above and beneath (sometimes some of the leaves 

 more or less glabrous in no. 23), otherwise not as above. 

 Involucral bracts about 5 mm long, imbricated in about 3 or 4 rows, 

 linear, with long-acuminate points, more or less tinged with 



