190 COMPOSITE, (composite family.) 



3. B. ehrysanthemoides, Michx. Glabrous, often decumbent at base, 

 a foot or two high : leaves lanceolate, rather viinutehj and evenly serrate: heads 

 rather large, little or not at all nodding: outer involucre seldom surpassing the 

 inner, conspicuouslij surpassed hij the oval or broadly oblong raiis: akenes 2 to 

 4-awned. — Wet grounds, across the continent ; on the plains around Denver. 



§ 2. Akenes narrow, linear-tetragonal ; the outer shorter and more truncate tlian 

 the inner, which gener ally taper upward: outer involucre seldom foliaceous or 

 enlarged : leaves (in ours) all once to thrice 3 to b-nately parted or divided, and 

 the raijs inconspicuous or none. 



4. B. bipinnata, L. Primary and secondary divisions of the leaves 

 rather ovate or deltoid-lanceolate in circumscription, and the lobes mostly acute : 

 akenes all slender, the inner ones 5 to 9 lines long, outermost moderately shorter 

 and thicker: awns 3 or 4, sometimes only 2. — A common weed in waste 

 ground througliout the continent. Commonly known as " Spanish Needles." 



5. B. tenuiseeta, Gray. A foot or two high, branched from the base, 

 sparsely liirsute or glabrous: leaves 2 to 3-ternately or pinnately dissected into 

 narrow linear lobes : heads on naked rather long and stout peduncles, many- 

 flowered, 4 or 5 lines high in flower : akenes glabrous, 2-awned ; inner 5 lines 

 long, with tapering summit ; outermost 3 lines long, stouter and with broad 

 summit and usually short awns : rays yellow, mostly surpassing the disk. — 

 PI. Fendl. 86. Along water-courses, Colorado, New Mexico, and Arizona. 



44. THELESPERMA, Less. 



Smooth and glabrous perennials : with opposite usually finely dissected 

 leaves, and pedunculate heads : the rays golden yellow. 



* Lobes of the disk-corollas linear or lanceolate, longer than the throat : pappus 

 evident: .chaff of receptacle falling with and partly embracing the akenes. 



\. T. ambiguum, Gray. A foot high, spreading by creeping roof stocks, 

 rather rigid and naked above: leaves bipinnately divided into narrowly linear 

 or filiform lobes : brctcfs of the outer involucre 8, subulate-linear, almost equalling 

 or half the length of the inner, whicli are connate to or above the middle : rays 

 broad, over ^ inch long, rarely wanting : disk usually purple turning brownish : 

 cuter akenes becoming coarsely papillose ; the stout pappus-scales not longer than 

 fie width of the akene. — Proc. Am. Acad. xix. 16. T. flifolium of most of 

 the Western Keports. From Montana to Colorado, New Mexico, and W. 

 Texas. 



2. T. graeile, Gray. More rigid, a foot or two high, from a deep root, 

 less branched, naked above : leaves once or twice 3 to 5-nately divided or 

 parted into filiform-linear or broader lobes, or some upper ones filiform and 

 entire : bracts of the outer involucre 4 to 6, rery short, ovate or oblong ; of the 

 inner one connate to above the middle, the edges of their lobes slightly scari- 

 ous : disk mostly yellow, scarcely brownish after anthesis : akenes less papillose 

 or rougliened, the breadth of the summit exceeded by the subulate awns: rays usu- 

 ally none, rarely present and 2 or 3 lines long, — Loc. cit. Plains, Nebraska 

 and Wyoming to W. Texas and Arizona. 



