516 COMPOSITAE (COMPOSITE FAMILY) 



spinulose- tipped: rays 20-30, bluish shading to white: pappus rather coarse 

 and dingy; achene short-pubescent. Sandy plains; Colorado and Wyoming. 



22. Aster Ported Gray, Proc. Am. Acad. 16: 99. 1881. Stems 1-3 dm. 

 high, glabrous and smooth (except ciliolation of lowest leaves), either simple 

 or branching above: leaves linear or the lower spatulate-linear, 5-10 cm. long, 

 2-5 mm. wide; radical narrowly spatulate: heads broad, rather small (6-8 mm. 

 high), thyrsoidly or cprymbosely arranged; bracts rigid, narrow, with subulate, 

 green, nearly erect tips: rays numerous, bright white, 8 mm. long: achenes 

 minutely pubescent. Common in the Colorado mountains. 



23. Aster laevis L. Sp. PI. 876. 1753. Rather stout, 5-12 dm. high, rigid: 

 leaves ovate or oblong to lanceolate, 9-12 cm. long, decreasing upward; the 

 radical and lowest cauline contracted below into a winged petiole ; the upper all 

 with auriculate or subcordate partly clasping base: heads sparsely thyrsoid- 

 paniculate, on short and rigid branchlets; involucre campanulate or obscurely 

 turbinate; the whitish coriaceous bracts bearing abrupt rhomboid or deltoid 

 short green tips: rays 20 or 30, broadish, sky-blue verging to violet. Eastern 

 slopes of the Rocky Mountains and eastward across the continent. 



24. Aster Geyeri (Gray) Howell, Fl. 308. 1897. Whole plant very smooth 

 and glabrous; stem stout, 3-7 dm. high, rigid: leaves ovate or oblong to lanceo- 

 late, 9-12 cm. long, decreasing upward to subulate bracts; the radical and 

 lowest cauline contracted below into a winged petiole; the upper all with auricu- 

 late or subcordate partly clasping base: heads sparsely thyrsoid-paniculate, 

 on short and rigid branchlets; involucre campanulate, the whitish subcor- 

 iaceous bracts mostly attenuate-acute, with obscurely green tips: rays 20-30, 

 broadish, sky-blue to violet: achenes glabrous or nearly so, 4-5-ribbed. 

 Wyoming to Idaho and Montana. 



25. Aster Lindleyanus T. & G. Fl. 2: 122. 1842. Glabrous or sparingly 

 pubescent, 3-10 dm. high, branched above: leaves rather thick, glabrous or 

 slightly pubescent, especially on the veins; the lower and basal ones cordate 

 at the base, sharply serrate, ovate, acute or acuminate, 5-10 cm. long, with 

 slender naked petioles; upper leaves ovate or lanceolate, less serrate or en- 

 tire, sessile or with margined petioles, those of the branches lanceolate or 

 linear-lanceolate, smaller: heads few, 8-10 mm. high; bracts imbricated, gla- 

 brous or nearly so, the tips green: rays 10-2Q, blue or violet, 6-10 mm. long 

 pappus nearly white. The form in our range is not typical of this species; 

 Colorado to Montana and thence nearly across the continent. 



26. Aster caerulescens DC. 1. c. 235. Tall, 5-15 dm. high, paniculately 

 polycephalous, from nearly glabrous and smooth to scabrous-pubescent : leaves 

 lanceolate to linear, entire or the larger with a few denticulations, 5-12 cm. 

 long: heads rather crowded, 7-10 mm. high; involucre of narrowly linear or 

 more attenuate erect bracts, either unequal and imbricated, or with some 

 loose and slender exterior ones which equal the inner: rays purple, white or 

 violet, 6-10 mm. long. (A. fluvialis Osterh. Bull. Torr. Bot. Club 32: 611. 

 1905; A. Osterhoutii Rydb. 1. c. 31: 654; A. Wootoni Greene, Leaflets 1: 146. 

 1905; Brachyactis hybrida Greene, Leaflets 1: 147. 1905; A. salicifolius Lam. 

 in part, as to our range.) Wyoming to New Mexico and westward. 



27. Aster laetevirens Greene, Pitt. 4: 219. 1900. Stems very erect, 3-6 dm. 

 high, glabrous except as marked by lines of pubescence decurrent from the 

 leaves, commonly red or purple, otherwise pale and glaucescent, leafy, and 

 somewhat equably so, even to the narrow and fastigiate or broader and sub- 

 corymbose panicle: leaves lanceolate or oblong-lanceolate, sessile by a broad 

 and almost auriculate-clasping base, thinnish, light green or glaucescent, en- 

 tire or obscurely and remotely serrate-toothed, marked by a white midvein 

 and some fine less obvious reticulation: involucres turbinate or subcampan- 

 ulate; bracts narrowly lance-linear, very acute, the narrow light green 

 herbaceous tips with a fine but distinct white midnerve, the margins re- 

 motely serrulate-ciliolate : rays many, usually long and showy, pinkish to 

 rose-purplish. (Many specimens of this species have been variously referred 

 to A. salicifolius Lam. and A. paniculatus Lam., species which are scarcely 

 within our range.) Neaf streams; in Colorado and Wyoming. 



