240 ELE^rENTS OF BOTANY. 



on long and margined petioles which are clasping at the base, the 

 upper sessile or clasping, those of the branches A^ery small ; heads 

 numerous, racemose, | in. wide ; involucral bracts linear ; ray flowers 

 8-15, pale blue ; pappus white. July-October. Common on dry 

 soil, and very variable. 



3. A, PATENS Ait. Purple Aster. Stem erect, rough-pubes- 

 cent, widely branched above, 2-4 ft. high; leaves ovate-oblong to 

 lanceolate, thin, acute or obtuse, clasping by an auricled base, the 

 upper small and bract-like, with ciliate margins; heads numerous, 

 1 in. wide, on the ends of the paniculate branches; bracts linear; 

 ray flowers 20-30, blue or violet ; pappus tawny ; achenes pubescent. 

 July-October. Common on dry ground. 



4. A. CONCOLOR L. Silvery Aster. Root often tuberous; 

 stem erect, slender, smooth or pubescent above, simple, 2-3 ft. high ; 

 leaves lanceolate to oblong, entire, sessile, silky on both sides w^hen 

 young; heads numerous, terminating the peduncle-like branches, 

 the bracts lanceolate, appressed, with spreading tips ; ray flowers 

 10-15, lilac; achenes silky; pappus tawny. July-October. On dry, 

 sandy ground. 



5. A. DUMOsus L. Bushy Aster. Stem erect, slender, smooth, 

 much branched, 2-3 ft. high; lower leaves spatulate, dentate, the 

 upper nearly linear and entire, those of the branches subulate ; heads 

 very numerous, small, campanulate ; bracts linear, with spreading 

 tips; ray flowers 15-30, purple or white; achenes pubescent, pappus 

 white. July-October. Common and quite variable. 



VII. ERIGERON. 



Annual or perennial ; leaves alternate ; heads solitary, 

 panicled or corymbed, hemispherical, many-flowered, radiate ; 

 bracts nearly equal, in 1 or 2 rows ; receptacle naked ; ray 

 flowers numerous, pistillate, white to purple, disk flowers 

 tubular, perfect ; achenes compressed, 2-nerved ; pappus a 

 row of slender, scabrous bristles, often with an outer row of 

 chaffy scales or short bristles. 



1. E. Philadelphicus L. Fleabane. Perennial, often pro- 

 ducing runners ; stem erect, slender, hairy, branched above, 2-4 ft. 

 high ; leaves thin, entire or coarsely toothed, sessile, the lower spatu- 

 late-oblong, the upper lanceolate, clasping; heads in corymbs or pani- 

 cles, peduncled; bracts linear; ray flowers numerous, shorter than 

 the bracts, narrow, purplish ; achenes slightly pubescent ; pappus a 

 single row of bristles. April^uly. Common on low ground. 



2. E. ramosus (Walt.) B. S. P. Daisy Fleabane. Annual; 



