392 



CABDUACEAE. 



Aster laevis L., Smooth Aster, Xorth American, glabrous, with stout 

 leafy stems up to 3° higli, the leaves sessile, lanceolate to oblanceolate, thick, 

 smooth, entire or somewhat toothed, cordate-clasping at the base, the numerous 

 heads with an involucre of acute green-tipped bracts about 4" long, the blue or 

 violet rays 6"-12" long, is occasionally planted in flower-gardens. 



Aster cordifolius L., Blue Wood Aster, North American, seen at Dun- 

 barton in 1914, is 2°-4° high, glabrous, or nearly so, with slender-petioled, 

 ovate cordate serrate pointed thin leaves 2-5' long, and small heads, the 

 rays violet or blue, 3"-5" long. 



7. ERIGKRON L. 



Branching or scapose herbs, with alternate or basal leaves, and corymbose, 

 paniculate or solitary, peduncled heads, of both tubular and radiate (rarely all 

 tubular) flowers. Involucre hemispheric or campanulate, its bracts narrow, 

 nearly equal, imbricated in but 1 or 2 series in our species. Receptacle nearly 

 flat, usually naked. Ray-flowers, in our species, white, violet or purple, 

 pistillate. Disk-flowers yellow, tubular, perfect, their corollas mostly 5-lobed. 

 Anthers obtuse and entire at the base. Style-branches more or less flattened, 

 their appendages short, mostly rounded or obtuse. Achenes flattened, usually 

 2-nerved. Pappus-bristles fragile, slender, scabrous or denticulate, in 1 

 series, or often an additional outer shorter series. [Greek, early-old, alluding 

 to the early hoary pappus.] A genus of some 130 species, of wide distribution. 

 Type species: Erigeron acris L. 



Herbaceous species. 



Annual ; stem leafy. 



Perennial ; basal leaves tufted, the upper very small. 

 Shrubby species. 



1. E. onnuus. 



2. E. philadelphicus. 



3. E. DarrelUanus. 



1. Erigeron annuus (L.) Pers. 

 Sweet Scabious. Daisy Fleabaxe. 

 (Fig. 428.) Annual, sparingly pu- 

 bescent with spreading hairs; stem 

 erect, corymbosely branched. Leaves 

 thin, the lower and basal ones ovate 

 or ovate-lanceolate, mostly obtuse, 

 petioled, usually coarsely dentate, 

 2'-6' long, i'-2V wide, the upper 

 sessile or short-petioled, lanceolate, 

 oblong, or linear-lanceolate; heads 

 rather numerous, 5"-7" broad; bracts 

 somewhat hispid; rays 40-70, linear, 

 white, or commonly tinged with 

 purple, 2"-4" long; pappus double, 

 the inner a series of slender fragile 

 deciduous bristles, often wanting in 

 the ray-flowers, the outer a persist- 

 ent series of short, partly united, 

 slender scales. [Aster annuus L. ; 

 Stenactis annua Cass.] 



Local in fields, waste and culti- 

 vated grounds. Naturalized. Native 

 of North America. Flowers from spring 

 to autumn. 



