248 COMPOSITAE. 



Taraxacum taraxacum (L.) Karst. Dandelion. Glabrous or loosely pu- 

 bescent when young; leaves oblong or oblanceolate, variously pinnatifid, 

 the lobes usually toothed and turned backward, 10-20 cm. long; peduncles 

 10-30 cm. high; involucre cylindric, the inner bracts either linear or linear- 

 lanceolate, the outer similar but shorter and reflexed; heads many-flowered; 

 rays yellow; akenes brownish, spinulose above, the pyramidal apex abruptly 

 narrowed into a slender beak, twice as long as the body; pappus white, copious. 

 Abundantly introduced. 



369. AGOSERIS. 



Acaulescent annuals or perennials, with milky juice; leaves 

 radical, clustered; heads solitary, on scapes; flowers yellow, 

 rarely orange or purplish; bracts of the involucre in a few rows; 

 receptacle flat, not chaffy; pappus of copious white capillary 

 bristles, which are not plumose; corollas all ligulate; akenes 

 oblong or linear, terete, 10-ribbed, the apex contracted into a 

 neck or prolonged into a beak. 



Leaves glaucous; beak of the akene short. A. glauca. 



Leaves not glaucous; beak much longer than the body of the 

 akene. 



Annuals; heads small. A. heterophylla. 



Perennials; heads large. A. grandiflora. 



Agoseris glauca (Nutt.) Greene. Perennial, leaves lanceolate or linear, 

 entire or dentate or variously pinnatifid, acuminate or attenuate at apex, pale 

 or glaucous, glabrous or loosely pubescent, 10-25 cm. long; peduncles stout, 

 erect, usually glabrous or glabrate, except at the base of the involucre, 30-60 

 cm. high; involucre hemispherical, 20-35 mm. high, glabrous or nearly so; 

 acuminate, the outer shorter; corollas pale yellow; akene pubescent, 10-ribbed, 

 10-14 mm. long, attenuate into a stout nerved beak shorter than the body; 

 pappus white, copious, the slender bristles scabrous, longer than the akene. 

 Low ground, common and variable. 



Agoseris glauca scorzoneraefolia (Schrad.) Piper. Involucre pubescent; 

 otherwise as in the species. In dry ground, not rare. 



Agoseris heterophylla (Nutt.) Greene. Annual; leaves linear, lanceolate 

 or oblanceolate, entire or variously toothed or pinnatifid, 5-12 cm. long, loosely 

 pubescent; peduncles erect, pubescent or glabrate, 10-30 cm. high; involucre 

 campanulate, 1-2 cm. high, the bracts in two series, the outer shorter and 

 usually pubescent ; akenes numerous, oblong or fusiform, the outer ones or some- 

 tinu's all of them thicker, the ribs developed into wings which are sinuately 

 folded, all attenuate into a narrow beak, twice or thrice as long as the body; 

 pappus bright white, soft and copious. 



Agoseris heterophylla normalis Piper. Akenes with straight ribs, those of 

 the outermost often wing-like. Both the species and the subspecies are very 

 common. 



Agoseris grandiflora (Nutt.) Greene. Perennial, loosely pubescent or 

 glabrate; leaves lanceolate or oblanceolate, attenuate-acuminate to obtuse, 

 mostly pinnatifid into numerous lobes, 10-20 cm. long; peduncles stout, 30-60 

 1 111. high; involucre campanulate, tomentose at base, 3-4 cm. high, the bracts 

 in about 3 series; akenes fusiform, acutely 10-ribbed, 6 mm. long, attenuate 

 into a slender beak, 20 mm. long; pappus bright white, soft and capillary, 

 much shorter than the beak. Dry ground, common. 



