Flora of the Palouse Regio?i 199 



12 mm. high, densely glandular-pubescent: rays yellow, 12-16 mm. long: 

 tubes of disk-corollas hairy: akenes pubescent. Moist hillsides, common. 



335. SENECIO. 



Herbs or shrubby plants: leaves all alternate: heads usually sol- 

 itary or in corymbs, many-flowered: flowers yellow, all fertile; 

 ray-flowers pistillate or occasionally none: involucral bracts her- 

 baceous, mostly narrow, equal, in one row, or with a few short 

 outer bracts: receptacle flat or merely convex, naked: pappus of 

 very numerous and mostly white fine and soft capillary and 

 merely scabrous bristles: akenes terete or somewhat angled, usu- 

 ally 5-10-ribbed. 



Introduced annual. S. vulgaris. 

 Native perennials. 



Upper leaves reduced. S. columbianus. 

 Equally leafy to the top. 



Leaves triangular. S. triangularis. 



Leaves lanceolate. S. serra. 



S. vulgaris L. Annual, sparsely pubescent or glabrous, usually branch- 

 ed, 15-30 cm. high: leaves spatulate or oblong in outline, 1-3 cm. long, half- 

 clasping at base, pinnately-lobed, the lobes short and usually toothed: heads 

 few to many, in corymbs: involucre 5-7 mm. high, the inner bracts linear, 

 acute, often black-tipped, the outer few and short: rays wanting: akenes 

 puberuleut: pappus copious, white. Becoming common. 



S. COlumbiariUS Greene. Perennial, erect, 30-90 cm. high, floccose- 

 woolly when young, becoming glabrous: basal leaves spatulate, oblanceolate 

 or obovate, mostly acute, dentate, 10-30 cm. long, including the margined 

 petiole; cauline sessile and half-clasping, much smaller: dentate or laciniate: 

 heads numerous, in rather dense corymbs: involucre 5-6 mm. high, the linear 

 acute bracts often black-tipped. Low ground, common and variable. 



S. triangularis Hook. Perennial, glabrous throughout, 30-90 cm. high: 

 stem simple, leafy to the top: leaves narrowly or broadly triangular, acute 

 or acuminate, evenly dentate, truncate at base or the lower often cordate 

 .ind the upper cuneate, 5-15 cm. long, on short petioles: heads corymbed: 

 involucre 6-8 mm. high; bracts linear-lanceolate, acute, pubescent at tip: 

 rays 6-12, yellow. Along streams, Thatuna Hills. 



S, serra Hook. Perennial, glabrous, about 1 m. high, very leafy, simple 

 or branched above: leaves lanceolate, acute and usually cuspidate, serrate- 

 dentate or the small upper ones entire, 5-15 cm. long, all sessile by a 

 narrowed base: heads corymbed, very numerous: involucre 5-6 mm. high, 

 the bracts linear, acute: rays 5-10, yellow, 6-10 mm. long. Low ground, 

 common. 



336. ciRsrrM. 



Mostly biennial herbs: leaves alternate, sessile, mostly pinnatifid 

 and prickly: heads usually large, terminal, many-flowered: flow- 

 ers all tubular, perfect and all alike, rarely imperfectly dioecious: 

 involucre ovoid or spherical: bracts imbricated, in many rows, the 



