COMPOSITAE. 355 



490. TARAXACUM. 



Acaulescent biennials or perennials, with milky juice; leaves 

 radical, pinnatifid; heads large, on scapes; flowers yellow; re- 

 ceptacle flat, naked; involucre of 2 rows of tegules; pappus of 

 copious and white capillary bristles which are not plumose; 

 corollas all ligulate; akenes oblong or fusiform, angled, about 

 10-ribbed, attenuate at base, with a long filiform beak at the apex. 



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 tegules either linear or linear- 

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

 ray-flowers yellow; akenes brownish, spinulose above, the pyramidal apex 

 abruptly narrowed into a slender beak twice as long as the body; pappus 

 white, copious. 



A common weed, introduced from Europe. 



491. AGOSERIS. 



Acaulescent annuals or perennials, with milky juice; leaves 

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

 rarely orange or purplish; tegules 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. 



Ours all perennials. 



Akenes beakless; leaves glabrous; alpine plant. A. alpestris. 



Akenes beaked. 



Leaves glaucous and thinly tomentose; beak of akene 



short, stout, nerved. A. glauca aspera. 



Leaves not glaucous; beak of akene slender, nerveless. 

 Beak much longer than the body of the akene. 



Heads 2 cm. high. A. laciniata. 



Heads 2.S-3 cm. high. A. grandiflora. 



Beak about as long as the body of the akene. 

 Flowers orange; leaves mostly entire. 



Leaves lanceolate-spatulate; beak shorter than 



the body of the akene. A . aurantiaca. 



Leaves narrowly linear; beak longer than the 



body of the akene. A. gracilenta. 



Flowers yellow; leaves mostly lobed. 



Akenes with beak 12-15 mm. long; leaves 



mostly entire. A . elata. 



Akenes with beak 8-10 mm. long; leaves most- 

 ly lobed. A . apargioides. 



Agoseris alpestris (Gray) Greene. Glabrous; leaves spatulate to lanceo- 

 late, pinnately lobed or cleft into broad lobes or parted into narrow divisions; 

 scape erect, 4-10 cm. high; involucre campanulate, 15 mm. high; tegules in 

 2 indistinct series, all acuminate, the outer ovate-lanceolate; flowers yellow; 

 akenes columnar, 10-ribbed, beakless, as long as the capillary white pappus. 



On the higher peaks of the Cascade Mountains; first found on Mount 

 Adams by Suksdorf. 



