COMPOSITAE (COMPOSITE FAMILY) 527 



sutely ciliate or sometimes nearly glabrous, no glandular roughness: involucre 

 more or less villous-pubescent, only 5-6 mm. high: rays mostly pale purple. 

 (E. Parryi Canby & Rose, Bot. Gaz. 15: 65. 1890; E. Scribneri Canby, 1. c.; 

 E. vetensis Rydb. Bull. Torr. Bot. Club 32: 126. 1905.) In the highest 

 mountains of our range and extending far northward. 



18. Erigeron ursinusEat. Bot. King's Exp. 148. 1871. Stems 1-2 dm. high, 

 loosely caespitose: leaves green, mostly smooth and glabrous, but their mar- 

 gins more or less hirsute-ciliate, spatulate to narrowly oblanceolate ; cauline 

 ones lanceolate or linear and acute: involucre (6 mm. high) and naked summit 

 of flowering stem hirsute-pubescent : rays 40 or 50, purple, narrowly linear, 

 6 mm. long. Alpine and lower in our range and westward to California. 



18a. Erigeron ursinus gracilis (Rydb.) A. Nels. More leafy and the whole 

 plant more or less strigose-pubescent. (E. gracilis Rydb. Mem. N. Y. Bot. 

 Card. 1: 404. 1900.) Subalpine in open grassy places; Yellowstone Park. 



19. Erigeron Engelmannii A. Nels. Bull. Torr. Bot. Club 26: 247. 1899. 

 Crown w r oody, from nearly simple to numerously but very short-branched: 

 leaves numerous, crowded on the crowns, linear, on very slender petioles 

 which about equal the blade, closely subcinereous, somewhat ciliolate on 

 the petioles, 2-6 cm. long (including the petioles): stems weak, decumbent 

 or prostrate, moderately leafy, 3-6 cm. long, monocephalous or with 2 or 3 

 heads: peduncles short, ascending, 1 or more-bracted ; heads rather small; 

 involucre about 5 mm. high; the bracts equal, narrowly linear, acuminate, 

 dark green with light margins, ciliolate: rays white, broadly linear, 40 (more 

 or less), the ligules about 5 mm. long, equal (E. simulans Greene, PI. Baker. 

 3: 31. 1901). Stony slopes and foothills at middle elevations; Wyoming, 

 Colorado, and Utah. 



20. Erigeron Eatonii Gray, Proc. Am. Acad. 16: 91. 1880. Stems several 

 from the crown of a strong taproot, slender and weak, diffuse, 1-2 dm. long, 

 simple or with 2 or 3 monocephalous branches: leaves all linear, thickish, 

 minutely pubescent; the radical about 5 cm. long and the broadest 4 mm. wide: 

 heads only 6 mm. high; bracts of the sparsely hirsute involucre little unequal: 

 rays seldom over 20, at most 6 mm. long, white or purplish. (E. nematophyllus 

 Rydb. Bull. Torr. Bot. Club 32: 124. 1905.) On the lower slopes of the 

 mountains; Wyoming to Colorado and Utah. 



21. Erigeron poliospermus Gray, Syn. Fl. 1: 210. 1884. Caudex multi- 

 cipital, the branches short and crowded; stems simple, numerous, rather closely 

 pubescent with spreading unequal hairs, leafy below, naked-pedunculate above, 

 7-15 cm. long: leaves crowded on the crowns, short-hirsute all over, the mar- 

 gins strongly hirsute-ciliate especially on the petioles, linear-spatulate, 3-5 

 cm. long (including petiole) ; stem leaves several, similar but becoming smaller 

 upward: peduncles naked or with a filiform bract, monocephalous; heads 

 large, including the spreading rays 20-25 mm. broad; mvolucral bracts nar- 

 row, in 2 rows, hirsute, long-acuminate, with a dark green midrib: rays 20- 

 50, purple or violet. (E. wyomingensis and E, inamoenus A. Nels. Bull. Torr. 

 Bot. Club 26: 248. 1899.) Gravelly hills; Wyoming to Montana and Oregon. 



22. Erigeron luteus A. Nels. 1. c. 27: 33. 1900. Densely tufted on a multi- 

 cipital caudex : leaves closely crowded on the crowns, all narrowly linear with 

 slightly tapering, petiole-like base, subcinereous, 3-5 cm. long: stems mono- 

 cephalous, simple, scape-like but bearing 2 or more short leaves below, the pe- 

 duncular portion usually with 1 small bract, from barely exceeding the leaves to 

 about twice as long: heads 6-8 mm. high; the involucral bracts linear, acutish, 

 somewhat unequal and in 2 rows, rather shorter than the disk: rays 30-40, a 

 pure yellow, rather broad and short, the ligules only 3-4 mm. long: pappus in 2 

 series, the outer of very short, inconspicuous bristles; the inner bristles rather 

 sparse and coarse, nearly as long as the tube of the disk-corollas; achenes 

 minutely pubescent. (Chrysopsis hirtella DC. 5: 327. 1836; E. curvifolius 

 Piper, Bull. Torr. Bot. Club 27: 396. 1900.) Sandy stream banks; Yellow- 

 stone Park to the plains of the Columbia. 



23. Erigeron microlonchus Greene, Pitt. 3: 293. 1898. Slenderly fusiform 

 perennial root bearing at the crown a central tuft of leaves encircled by several 



