150 COMPOSITE. (COMPOSITE FAMILY.) 



4- 4- Stijie-appendages hardly exserted : aJcenes glabrous: involucre 15 to 20- 

 Jloicered : herbage glabrous throughout. 



3. B. Engelmanni, Gray. A span or two high, in tufts from a sub 

 terranean branching caudex : stems simple, very leafy up to the cymose- 

 glomerate heads : leaves all narrowly linear, an inch or two long, only a 

 line wide, rigid : bracts of the involucre regularly imbricated and appressed, 

 outer similar but short, all abruptly mucronate or short-cuspidate, slightly 

 greenish below the tip. — Proc. Am. Acad. xi. 75. Plains of Colorado at 

 Hugo Station. 



* * Heads narrow or small, ^-flowered, mostly numerous and crowded : involucre 

 of dry chartaceous more or less keeled bracts imbricated so as to form 5 con- 

 spicuous vertical ranks : shrubby and branching, with narrow entire leaves. 



+- Akenes and ovaries glabrous, 4 to 6-angled : pappus rigidulous : bracts of the 

 involucre acute or acuminate, numerous and strictly 5-ranked, 5 or 6 in each 

 veHical rank : herbage not punctate, slightly or not at all resinous. 



4. B. depressa, Gray. Obscurely puberulent and pale, a span or two high 

 from a decumbent Avoody base: branches leafy up to the glomerule or fas- 

 ciculate cyme of few heads : leaves short, about ^ inch or less long, lanceolate 

 or lowest rather spatulate, rigid, mucronote-acute, with carinate midrib and no 

 veins: heads ^ inch long: involucral bracts lanceolate, gradually acuminate 

 into an almost setaceous tip. — Plains of S. Colorado to New INIexico and S. 

 Utah. 



5. B. pulchella, Gray. Glabrous and green, shrubby, 2 or 3 feet high, 

 fastigiately much branched, very leafy up to fastigiate-cymose heads: leaves 

 narrowlij linear, plane, an inch or less long, rather obtuse, with ciliolate-scabrous 

 margins and 7mdrib not prominent : heads i to f inch long : involucral bracts 

 rigid-chartaceous, much carinate, acute and cuspidate-mucronate. — W. Texas 

 to New Mexico and Colorado. 



6. B. Bigelovii, Gray. Canescent with fne close tomentum when young, 

 glabrate, shrubby, a foot to a yard high, fastigiately much branched, rigid : 

 branches less leafy, bearing a few fastigiate-clustered heads, ^ to § inch high : 

 leaves nearly f I form : involucral bracts lanceolate, acute, thinnish, all pale. — 

 N. New Mexico and adjacent Colorado. 



t- 4- Akenes canescently pubescent or villous : herbage commonly graveolent and 



mostly becoming more or less resinous or viscid. 



*^ Leaves numerous, filiform : involucral bracts 3 in each vertical rank, mostly 



icith small subulate spreading or recurving tips. 



7. B. Greenei, Gray. Suffruticose, about a foot high, green and gla^ 

 brous, more or la«s balsamic-viscid : leaves very numerous on the branches, 

 filiform-acerose, but flat, and margins minutely scabrous: heads numerous 

 and fastigiate-cymose, 3 or 4 lines high. — Proc. Am. Acad. xi. 75. Colo- 

 rado, on the Huerfano Plains and near Twin Lakes ; also in Utah. 



^ -^ Leaves numerous, from filiform-linear to broadly linear or lanceolate : bracts 

 of the involucre obtuse or somewhat acute. 



8. B. graveolens, Gray. A foot to a yard or more high, bearing nu- 

 merous crowded heads : these h or § inch high : leaves mostly fiocculent-tomen 

 tose when young, often glabrate in age, not rigid ; the larger spatulate-Hnear, or 



