Rydberg : Rocky Mountain flora 469 



auriculate-clasping; heads in a rather dense corymb, 8-9 mm. 

 high; involucres vSomewhat turbinate and floccose at the base, 

 5-6 mm. high, 6-7 mm. broad; bracts linear, acute, carinate, 

 brownish-black on the backs, yellowish brown on the margins; 

 rays orange, about 6 mm. long, 2 mm. wide; achenes glabrous. 



This species resembles most the eastern Senecio tomentosns 

 in habit and pubescence, but differs in the shorter blades of the 

 basal leaves, which are obovate or oval instead of ovate, in the 

 dark involucres, and the glabrous achenes. It grows in meadows 

 at an altitude of 1500-2000 m. 



Utah: Near divide, head of American Fork Canon, July 29, 

 1885, Leonard 143 (type, in herb. N. Y. Bot. Card.); Wahsatch 

 County, near Midway, July 6, 1905, Carlton & Garrett 6701. 



Senecio Tweedyi sp. nov. 

 Senecio flavovirens Rydb. Bull. Torrey Club 27: 181, in part. 



1900. 

 Senecio Balsamitae A. Nels., Coult. & Nels. New Man. Cent. 



Rocky Mts. 583, in part. 1909. 



Perennial, with a rootstock; stem glabrous, or slightly floccose 

 at the leaf-axils, 4-6 dm. high, striate; basal leaves 3-15 cm. long, 

 petioled; blades elliptic or oval to oblanceolate, crenate-dentate, 

 often lyrate-pinnatifid with a few lobes below the large terminal 

 one; lower stem-leaves similar, but more pinnatifid; upper stem- 

 leaves deeply pinnatifid, with oblong toothed divisions; heads 

 corymbose, 9-10 mm. high; involucres glabrous, somewhat tur- 

 binate at the base, about 8 mm. high and as broad; rays narrow, 

 bright yellow, 8-10 mm. long and a little over i mm. wide; achenes 

 hispidulous on the margins. 



This species has been mistaken for Senecio flavulus Greene 

 {S. flavovirens Rydb.). In fact, the type was included in the orig- 

 inal publication of S. flavovirens and the characters of the achenes 

 were drawn from it. The type of 5. flavovirens is just in bloom 

 and the achenes only slightly developed, but a closer investigation 

 shows that they are perfectly glabrous. So are the young achenes 

 of all the specimens cited under 5. flavovirens except Tweedy 586. 

 As this had well-developed achenes, I unfortunately described 

 the achenes from it. The type of S. flavovirens and the other 

 specimens cited under it, with the single exception mentioned, 

 belong to S. flavulus Greene, described a few months earlier. Be- 



