158 COMPOSITE. (composite family.) 



uppermost around the sessile (£ inch) heads and seldom surpassing them: invo- 

 lucra] bracts more obtuse: pappus of the ray from £ to -£ the length of that 

 of the disk. — Mountains of Wyoming to Utah and Nevada. 

 «* ++ ++ Heads about $ inch long: sessile among the rosulate leaves: herbage 

 soft-lanaU : j/n/i/ms deciduous in a rim/. 



10. T. spathulata, Nutt. Depressed an;! multicipital, forming a tuft an 

 inch or so high : leaves crowded, spatulate, densely villous-lanate ; the upper 

 about equalling the heads : bracts of the involucre oblong-lanceolate, acute ■ 

 rays rather short, pinkish : pappus of ray and disk similar, of slender bristles. 

 — Mountains of Wyoming. 



++ ++ ++ -^ Heads small, \ inch high {exclusive of the rays), mostly short-pedun- 

 culate : involucre of broadly lanceolate and barely acute bracts : caulescent 

 and branching: pappus of the ray shorter, commonly of chaffy bristles. 

 = Green and glabrate. 



11. T. glabella, Gray. An inch or two high, nearly simple, spnrsely 

 pilose-pubescent when young : leaves thickish, soon glabrous, spatulate, an 

 inch or less long, including the usually slender petiole ; the uppermost usually 

 surpassed by the slender and naked peduncle : involucre glabrous. — Proc. 

 Am. Acad. xvi. 86. S. W. Colorado, Newberry. 



= = Cinereous with fine and close pubescence, flowering from near the ground at 

 first, but becoming taller (4 to 10 inches high) and loosely branching. 



12. T. Fendleri, Gray. Leaves linear: bracts of the involucre unequal, 

 in about 3 ranks, acute. — PI. Fendl. 70. New Mexico and S. Colorado. 



13. T. Strigosa, Nutt. Flowering when only h inch high, often attain- 

 ing a span in height : early leaves spatulate ; later ones linear : heads rather 

 smaller : bracts of the involucre broader, acutish, in about 2 ranks, the outer 



13. ASTER, Tourn. Starwort. Aster. 



The largest and by far the most difficult of our genera, not naturally sepa- 

 rated from Erigeron. All are herbs, mostly perennial, and especially charac- 

 teristic of North America. Includes Machaeranthera and Diplopappus. 



§ 1. Involucral bracts (at least the outer ones) with green herbaceous tips or 

 appendages, or wholly or partly foliaceous, imbricated or many-ranked, their 

 margins not scar ions : akenes from obovate-oblong to linear, 3 to several- 

 nerved: pappus rather fine and soft (in one or two species more coarse and 

 rigid), simple (with no exterior series). — Aster proper. 

 # Involucre well imbricated : the brads appressed and coriaceous, with more or 

 less spreading herbaceous tips: akenes narrow, 5 to 10-nerved: pappus more 

 rigid than in the following groups: rays showy, blue or violet: leaves firm, 

 acutely serrate, more or less scabrous, none of them cordate or clasping ; the 

 radical tapering at base into margined petioles. 



1. A. SibiriCUS, L. A span to afoot high, somewhat cinereous-pubescent 

 or puberulent, or the foliage scabrous : heads solitary, terminating the stem 

 or corymbiform branches : leaves oblong-spatulate to broadly lanceolate, 1 to 

 3 inches long : involucre 3 lines high, shorter than the disk ; its bracts narrowly 



