420 ORDER 70. COMPOSITE. 



very silky; pappus simple. 2 Herbs with alternate Ivs. and close 

 corymbs. Rays white. 



" S. solidagineus Nees. Smooth; Ivs. linear-ollanceolate, obtuse, entire, sessile, 

 obsoletely 3-veined, rough on the margin ; corymb fastigiate ; hds. aggregate, 

 subsessile, 5-rayed; scales obtuse, white, with green tips; pappus white. In 

 woods, Can to La. Very elegant. Sts. clustered, slender, simple, abou.t 2f high. 

 Lvs. smooth, 1 to 2' by 3 to 5". Hds. small (3'' long). Invol. oblong. Scales with 

 conspicuous green tips. Rays long, white. Jl., Aug. (Aster solidaginoides MX.) 



2 L. conyzoides Nees. St. somewhat pubescent, simple, corymbus at top; Ivs- 

 oval-lanceolate, smooth beneath, slightly 3-veined, narrowed at base, acute, tho 

 upp jr ones sessile, nearly entire, the lower narrowed into tho petiole, serrate ; in- 

 vol. cylindrical, the scales oval, obtuse, appressed, slightly reflexed at summit; 

 rays 5, short, pappus rusty. Common in woods and thickets, Mass to Flor. 

 Stems somewhat 5-angled, 1 2f high. Leaves somewhat fleshy. Ray short, 

 but longer than the disk, white. July, Aug. (Aster Willd. Conyza aster- 

 oides L.) 



3 S. tortifolius Nees. Grayish-pubescent, roughish, corymbous above ; Ivs. 

 short, oblong-obovate, sessile, twisted to a vertical position, and both sides alike 

 minutely scabrous ; scales regularly imbricated in many rows, the green tips 

 slightly spreading ; pappus white. Dry woods and barrens, Va. to Fla. and La. 

 Height about 2f, often branched below. Lvs. 8 to 12" long, obtuse or acute. Hds. 

 larger than in the others, about 5" long. Sept., Oct. 



18. ASTER, L. (Gr. aorfip, a star ; from the radiated flowers.) Hds. 

 radiate ; involucre oblong, imbricate ; scales loose, often with green 

 tips, the outer spreading ; disk flowers tubular, ; ray flowers $ , in one 

 row, generally few (6 100), ligulate, oblong, 3-toothed at apex, finally 

 revolutc ; receptacle flat, alveolate ; pappus simple, capillary, scabrous ; 

 achenium usually compressed. A large genus of 2J! herbs, very abun- 

 dant in the U. S., flowering in late summer and autumn. Lvs. alter- 

 nate. Disk fls. yellow, changing to purple, ray flowers blue, purple or 

 white, never yellow. 



BIOTIA. DC. Scales closely imbricated, slightly tipped with preen. lids, corymbous, 



rays 6to 15, white or roseate. Lvs. cordate, petiolate, serrate, large Nos. 1, 2 



CALLIABTRUM, T. & G. Scales loosely imbricated, with green spreading tips. Heads 

 corymbous or few, large, rays 12 to 30, violet. Leaves never cordate, rigid ; pappus 



unequal, rigid, the inner slightly club-shaped. Leaves all or the lower serrate Nos. 3 ft 



Leaves entire Nos. 6, 7 



ASTER proper. Scales (variously) imbricated, with green tips or wholly green, lids, 

 paniculate or racemous. Pappus soft, equal (none club-shaped), (a) 

 a Leaves clasping with a cordate or auriculate base, (b) 

 a Leaves sessile or petiolate, none of them cordate or auriculate. (c) 



a Leaves petiolate, tho lower cordate, evidently senate Nos. 8, 9 



entire or obscurely serrate Nos. 10 12 



b Leaves entire, very small (1 to S" long), erect or reflexed Nos. 13, 14 



middle size (1 to 8' lonir), Achenia silky Nos. 1517 



Achenia smooth Nes. 20, 85 



b Leaves serrate (more or less). Scales spreading, equal, in 2 rows No. 18 



Scales imbricated, in 3 to 5 rows Nos. 1921 



C Leaves silky on both sides alike. Pappus tawny Nos. 22, 23 



C Leaves not silky. Involucre closely imbricated, (d) 



Involucre squarrous, the scales spreading, (e) 



d Leaves all entire. Scales of the involucre obtuse Nos. 24, 25 



Scales acute or mucronate Nos. 26 28 



d Leaves (lower) sharply serrate. Heads larger (4 to 6" long) Nos, 29, 30 



Heads small (2 to 3" long) Nos. 31, 32 



6 Scales obtuse, in several rows, unequal. Leaves also obtuse. .Nos. 33, 84 



e Scales acute, in several rows, unequal. Pappus tawnv Nos. 35 '37 



Pappus bright .... . .Nos. 3840 



e Scales acute, in one row, equal. Leaves linear. Heads solitary.. .No. 41 

 ScARios.*. Scales (variously) imbricated, with scarious margins and destitute of 

 green tips, (f) 



f Leaves lanceolate broadly or narrowly. Scales rather obtuse Nos. 42 14 



f Leaves subulate or linear. Scales very acute. Heads large, few Nos. 45, 46 



Heads small, many Nos. 47, 48 



