COMPOSITAE. 275 



leaves entire or more or less lobed, oblong, obtuse, the blades 2-4 cm. long, 

 shorter than the petioles; upper leaves sessile or nearly so, pinnately lobed or 

 parted; heads cymose, slender peduncled; involucre cylindric to campanulate, 

 5-7 mm. high; bracts linear-lanceolate, acute, the outer short ones wanting; 

 rays 8-12. Common on gravelly soil about Spokane. Usually confused with 

 S. canus Hook, which has much looser pubescence. 



Senecio 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 and 

 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. In moist places in the mountains. 



Senecio 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. 



Senecio serra lanceolatus (T. & G.) Piper. Leaves all entire or nearly so. 

 Waitsburg, Horner. 



Senecio hydrophilus Nutt. Perennial, wholly glabrous and slightly glau- 

 cous; stems erect, 60-100 cm. high, stout; leaves fleshy with obscure veins, 

 entire or nearly so, the basal oblanceolate, short-petioled, 10-30 cm. long; 

 cauline sessile or half-clasping, lanceolate; heads numerous, in a dense cyme, 

 short-peduncled; involucre cylindric, 6 mm. high; bracts 8-12; rays small, 

 few or sometimes wanting. In wet places especially on river banks. 



Senecio exaltatus Nutt. Very similar to S. atriapiculatus but taller, 60- 

 90 cm. high, and less pubescent or even wholly glabrous; leaves larger, thinner, 

 the basal oblong to spatulate, the blades 10-15 cm. long, on petioles nearly as 

 long; heads loosely corymbose; involucral bracts about 13, 5-7 mm. long. 

 In moist meadows and copses. 5. hydrophiloides Rydb. seems to be only a 

 large wholly glabrous form. 



Senecio atriapiculatus Rydb. Perennial, erect, 30-60 cm. high, sparsely 

 floccose- woolly; basal leaves spatulate, oblanceolate or obovate, mostly acute, 

 dentate, 5-10 cm. long, including the margined petiole; cauline sessile and 

 half-clasping, much smaller, often dentate or laciniate; heads numerous, in 

 rather dense corymbs; involucral bracts 6.5-8.5 mm. high, linear, acute, black- 

 tipped. Common on hills. 



Senecio condensatus Greene. Much like S. atriapiculatus but stouter 

 and rather succulent; upper leaves not much reduced; heads densely clustered. 

 On rocky ridges in the Blue Mountains. 



409. CROCIDIUM. 



Small annual herbs with alternate leaves; heads solitary, 

 terminal, small, radiate, the flowers all fertile; involucre hemi- 

 spherical, of 8-12 thin herbaceous bracts in one row; ray-flowers 

 about 12, yellow; disk- flowers more numerous, yellow; style 

 branches short and broad, with large appendages; pappus of one 

 row of deciduous equal, white barbed bristles but none in the 

 ray-flowers. 



