RUDBECKIA— SENECIO 291 



b. Leaves 3-7-divided ; stems 3-6 ft. high, usually 



smooth R. lacinidta 



2. Rays none 



a. Leaves entire or toothed, disk 3-5 cm. long R. occidentalis 



b. Leaves pinnately parted; disk 5-7 cm. long R. montana 



Rvdbergia G. eene 1898 Rvdbergia 



(Named for the American botanist Rydberg) 



PI. 41, fig. 7. 



Heads with yellow pistillate ray-flowers, disk-flowers yellow, perfect, 

 achenes top-shaped, ribbed or angled, hairy, pappus of 5-12 white scales, 

 usually long-pointed ; receptacle flat, without chaff, involucre hemispheric, 

 the woolly bracts in several rows ; heads solitary ; leaves 2-5-parted or 

 lobed into linear divisions, upper sometimes entire; alpine perennial. 



1. Leaves and involucre woolly; rays 30 or more, 



12-16 mm. long R. grand 'iflora 



2. Leaves smooth or nearly so ; involucre merely 



hairy; rays 12-16, 6-8 mm. long R. Bvandcgei 



Senecio Linne 1753 Groundsel 



(Lat. senex, old man, perhaps from the white pappus) 



PL 40, fig. 4. 



Heads with yellow pistillate ray-flowers or none, disk-flowers yellow, 

 perfect, achenes oblong, rounded, ribbed, pappus of hair-like bristles ; re- 

 ceptacle flat, without chaff, involucre bell-shaped to cylindric, the main 

 bracts in 1 row, usually with some shorter ones ; heads solitary or in 

 corymbs or panicles ; leaves alternate or basal, entire or pinnatifid ; annual 

 or perennial. 



1. Heads large, 15-25 mm. high 



a. Heads with rays 



(1) Stem leaves clasping at base, usually sharp- 



ly toothed S. ample ct ens 



(2) Stem leaves distinctly petioled, not clasping 



(a) Leaves round or nearly so, smooth, 



mostly basal ; heads erect 5". soldanclla 



(b) Leaves spatulate to obovate, tapering in- 



to the petiole ; heads nodding 

 x. Stems 1-6 in. high; leaves somewhat 

 lobed. white woolly; heads single; 

 rays 10-15 mm. long 5". taraxacoides 



