580 COMPOSITAE (COMPOSITE FAMILY) 



16. Senecio integerrimus Nutt. Gen. 2: 165. 1818. Stem simple, strict, 

 3-5 dm. high: leaves somewhat fleshy, wholly glabrous and entire; the lower 

 oblong-lanceolate or elongated-oblong; the upper becoming gradually much 

 reduced and linear-lanceolate: heads few, mostly in a simple corymb or in a 

 subumbellate cyme, medium size with rather conspicuous rays; bracts of 

 the involucre narrow. This species seems to occur in just the form originally 

 characterized, and when thus limited it is a plant of the plains region adjacent 

 to the " Great Bend " of the Missouri, hence scarcely in our range. 



17. Senecio perplexus A. Nels. Bull. Torr. Bot. Club 27: 271. 1900. Root- 

 stock short, with numerous semifleshy roots; the single stem erect, rather 

 stout, 2.5-5 dm. high, loosely arachnoid or floccose-woolly when young as are 

 also the leaves, becoming glabrate but usually some of the woolly hairs per- 

 sisting even at maturity, rather leafy below: leaves entire or denticulate, 

 often crisped on the margin; the lower leaves ob lanceolate or broader or 

 tapering uniformly to both ends, mostly obtuse, 5-10 cm. long, the margined 

 petiole usually shorter than the blade; the middle leaves mostly sessile and 

 narrower; the uppermost small and bract-like: heads several (8-15), in a 

 cymose corymb, 10-12 mm. high, the central peduncles very short, the lower 

 or outermost elongating and often overtopping the others; the rays conspic- 

 uous, few (5-10); the involucral bracts linear, black-tipped, about 7 mm. long: 

 achenes brownish, finely striate, glabrous, linear, equaling or longer than the 

 fine soft pappus. S. lugens of the Manual and of Gray's Syn. FL, in large part. 

 (S. columbianus Rydb. in Fl. Col., not S. columbianus Greene, of which S. 

 atriapiculatus Rydb. is a synonym.) Exceedingly common at middle ele- 

 vations in our range. 



17 a. Senecio perplexus dispar A. Nels. Merely one of the many forms 

 of this variable species, characterized by its somewhat greater size, the 

 somewhat longer and slender petioles, and the striking inequality in the length 

 of the rays of the subumbellate cyme. (S. dispar A. Nels. 1. c. 272; S. Hookeri 

 Rydb. in Fl. Col., not of Gray.) Same range as species. 



18. Senecio atratus Greene, Pitt. 3: 105. 1896. Stems several or many, 

 tufted, decumbent at base, stoutish, 3-6 dm. high, leafy up to the dense 

 compound corymbiform cyme of small heads; herbage finely tomentose even 

 in maturity: radical leaves 1.5-2.5 dm. long, oblanceolate, acutish, dentate 

 or denticulate, those of the stem smaller and gradually diminished in size 

 toward the inflorescence: bracts of the narrow involucre only 8 or 10, firm, 

 oblong, obtuse, either wholly black or the inner ones with blackened mid- 

 vein and tip: rays few or none; disk-corollas salmon-color: achenes greenish, 

 glabrous; pappus firm, persistent. S. lugens foliosus in part. (S. milleflorus 

 Greene, Pitt. 4: 116. 1900.) In the mountains of Colorado. 



19. Senecio altus Rydb. Mem. N. T. Bot. Gard. 1: 443. 1900. Stems 

 6-10 dm. high, striate, sparingly woolly when young, leafy below: basal leaves 

 2-3 dm. long, rather firm, oblanceolate, tapering into a winged petiole, sin- 

 uately dentate, more or less woolly when young; lower stem leaves similar, 

 smaller, short-petioled or subsessile, the upper much reduced, bract-like, 

 linear-lanceolate, distant: heads in a contracted corymbiform cyme, about 

 1 cm. high; bracts linear, rather thick, brownish and tipped with black: rays 

 about 8 mm. long: achenes hispidulous, especially on the angles, short. S. 

 lugens foliosus in part. Wet meadows at middle altitudes; Wyoming, Mon- 

 tana, and Idaho. 



20. Senecio canus Hook. Fl. Bor. Am. 1: 333. pi. 116. 1834. Perennial, 

 densely and persistently white-tomentose to the inflorescence; stems slender, 

 usually tufted, 1-3 dm. high: basal and lower leaves spatulate or oval, entire, 

 or rarely somewhat repand, very obtuse, 3-5 cm. long, narrowed into petioles; 

 upper leaves oblong or spatulate, obtuse or acute, mostly sessile, smaller, en- 

 tire or dentate: heads several or numerous, 10-14 mm. broad, usually slender- 

 peduncled ; involucre campanulate, or at first short-cylindric ; the bracts linear- 

 lanceolate, acute, sparingly tomentose or glabrate, usually with no exterior 

 smaller ones: rays 8-12: achenes glabrous, at least below. (S. Harbourii 

 Rydb. Bull. Torr. Bot. Club 33: 158. 1906; S. Howellii Greene, Bull. Torr. 



