COMPOSITAE (COMPOSITE FAMILY) 579 



thickly dentate, deltoid-lanceolate or the lower triangular-hastate or deltoid- 

 cordate and the uppermost lanceolate with cuneate base: heads about 12 mm 

 high; involucre campanulate, mostly 25-30-flowered, the oblong-linear rays 

 6-12. (S. salient Rydb. Bull. Torr. Bot. Club 24: 298. 1897; S. trigonophyllus 

 Greene, Pitt. 3: 106. 1896.) Wet places in the mountains of our range 

 and westward to the coast States. 



10. Senecio serra Hook. 1. c. 333. Strict, 7-12 dm. high, very leafy, com- 

 monly branching at summit, and bearing numerous corymbosely paniculate 

 smaller heads: leaves 8-14 cm. long, all lanceolate and tapering to both 

 ends, sessile by a narrow base, or the lowest short-petioled, usually with the 

 whole margin thickly serrate or serrulate with very acute salient teeth: in- 

 volucre obiong-campanulate, 20-30-flowered : rays 5-8, oblong-linear. (S. 

 andinus Nutt. Trans. Am. Phil. Soc. 7: 409. 1841; S. serra integriusculus 

 Gray, Syn. Fl. 1: 387. 1886.) Along streams, middle elevations and upward; 

 Northern Wyoming, northward and westward. 



10a. Senecio serra admirabilis (Greene) A. Nels. Not constantly separable 

 from the species, usually of more vigorous growth and with fewer and larger 

 heads but these often 40 or more. (S. admirabilis Greene, Erythea 3: 23. 

 1895.) In the mountains of Colorado and southern Wyoming. 



11. Senecio crassulus Gray, Proc. Am. Acad. 19: 54. 1883. Stems 2-4 dm. 

 high, glabrous, 5-7-leaved, bearing 3-8 pedunculate rather large and thick 

 heads: leaves oblong-lanceolate, apiculate-acute, 5-21 cm. long; the radical 

 and lowest cauline spatulate or obovate-oblong, narrowed into a short-winged 

 petiole; the upper sessile by partly clasping or decurrent base: involucre 40-50- 

 flowered, of 12 fleshy-thickened but thin-edged bracts, the base also thick- 

 ened, the whole becoming conical and many-angled in fruit: rays about 8. 

 (S. semiamplexicaulis Rydb. Mem. N. Y. Bot. Gard. 1: 440. 1900; S. lapathi- 



folius Greene, PI. Baker. 3: 25. 1901.) In the mountains of our range. 



12. Senecio rapifolius Nutt. Trans. Am. Phil. Soc. 7: 409. 1841. Stem 

 rather low, only 2-4 dm. high: leaves ovate or oblong, very sharply and un- 

 equally dentate throughout, somewhat fleshy; the radical tapering into a 

 petiole; the cauline clasping by a broad subcordate base: heads numerous, 

 cymose-paniculate, only 5-6 mm. high, always rayless, about 15-flowered. 

 Middle elevations on the eastern slope of the Rocky Mountains. 



13. Senecio hydrophilus Nutt. 1. c. Very glabrous and smooth, tall, 

 strict and simple-stemmed, with a cluster of coarse fibrous roots, 5-15 dm. 

 high: leaves fleshy-coriaceous, all entire or barely denticulate, mostly lanceo- 

 late; the radical oblanceolate and stout-petioled, sometimes 3 dm. long; the 

 upper cauline sessile or partly clasping: heads numerous in a branching cyme; 

 bracts 8-12: disk-flowers 15-30: rays 3-6 and small, or none. (S. hydrophi- 

 loides Rydb. 1. c. 441.) In wet or partially flooded grounds; throughout our 

 range and northward and westward. 



14. Senecio glaucescens Rydb. 1. c. The short caudex with a cluster of 

 fibrous roots, glabrous or at first slightly hairy; stem 2-7 dm. high, striate, 

 shining, often tinged with red: basal leaves and lower stem leaves 5-10 cm. 

 long, spatulate or oblanceolate or even oval, callous, dentate or very rarely 

 subentire, acute or obtuse, with a distinct winged petiole, rather thick and 

 often somewhat glaucous; upper stem leaves reduced, lanceolate and sessile: 

 cyme corymbiform; heads about 1 cm. high; bracts linear-lanceolate, acute, 

 with conspicuous black tips: rays about 8 mm. long: achenes oblong-cylindric, 

 glabrous. (S. exaltatus Nutt. 1. c. as to our range; S. Flintii Rydb. Bull. Torr. 

 Bot. Club :>:J: 157. 1906.) Colorado and Utah to Montana and Idaho. 



15. Senecio anacletus Greene, Pitt. 4: 307. 1901. Stem 3-6 dm. high, from 

 a short rootstock or caudex: leaves thickish and firm; the radical obovate 

 to oblong, obscurely veiny, mostly acute, numerously denticulate, 5-15 cm. 

 long, tapering into shorter wing-margined petioles; the cauline sessile, few 

 and oblong-lanceolate, or commonly only 1 or 2 small and bract-like ones sub- 

 tending the rather few-headed branches of the cyme: heads 10-12 mm. high; 

 involucral bracts linear: rays 6-10, conspicuous. (S. microdontus Heller, Bull. 

 Torr. Bot. Club 24: 497. 1897.) Southern Colorado, New Mexico, and Arizona. 



