598 COMPOSITAE (COMPOSITE FAMILY) 



106. TROXIMON Nutt. 



Herbs, mostly acaulescent, with tufted usually sessile basal leaves and 

 solitary heads of yellow or rarely purple flowers at the end of a naked or 

 bracted scape. Involucre campanulate or oblong, the bracts imbricated in 

 several rows, appressed or with spreading tips, membranous or herbaceous, 

 not thickened after flowering, the outer ones gradually shorter and broader. 

 Receptacle flat, naked or foveolate. Rays truncate and 5-toothed at the 

 apex. Anthers sagittate at the base. Style-branches slender. Achenes 

 oblong, obovate, or linear, 10-ribbed, not flattened, beaked at the summit. 

 Pappus of copious, slender, simple, white bristles. 



Achenes tapering to a stout-nerved beak shorter than the body; 



flowers yellow, often roseate in drying. 

 Leaves entire or coarsely and irregularly toothed. 

 Leaves more or less pubescent even in age. 



Narrowly lanceolate or linear, and often somewhat laciniate- 



toothed 1. T. pubescens. 



Lanceolate or oblanceolate, often broadly so and obtuse . 2. T. villosum. 

 Leaves glabrous at least in age; the involucre glabrous or some- 

 what pubescent. 

 Leaves not 2-ranked . . . . . . . 3. T. glaucum. 



Leaves 2-ranked, linear 4. T. parviflorum. 



Leaves narrowly linear, or laciniately parted into linear divisions 5. T. arachnoideum. 

 Achenes with slender beak, as long as or longer than the body. 



Flowers orange, in age or on drying often purplish; more or less 



woolly-pubescent under the involucre. 

 Plant low (1-2 dm.); leaves tapering to a short- winged petiole, 



or sessile . . .6. T. aurantiacum. 



Plant taller (2-5 dm.); leaves tapering into a long, slender, 



winged petiole 7. T. purpureum. 



Flowers yellow, scarcely changing when dry. 

 Involucre glabrous. 



Somewhat woolly-pubescent below the involucre on the 



peduncle . . . . . . . . 8. T. arizonicum. 



Not woolly-pubescent on the peduncle . . . 9. T. elatum. 



Involucre more or less pubescent ...... 10. T. montanum. 



1. Troximon pubescens (Rydb.) A. Nels. Perennial with a taproot and 

 short, branching caudex: leaves narrowly oblanceolate, about 1 dm. long, 

 5-15 mm. wide, acuminate, slightly glaucous but even in age villous-pubescent; 

 scape 1.5-3 dm. high, sparingly villous: involucre about 2 cm. high, villous 

 and somewhat viscid; bracts with a dark median line and sometimes tinged 

 with purple, the outer ones ovate-lanceolate, about two thirds the length of the 

 linear-lanceolate, long-acuminate inner ones: flowers yellow, the outer often 

 striate or tinged with purple: beaks of the achenes short and striate through- 

 out. (Agoseris pubescens Rydb. Bull. Torr. Bot. Club 28: 511. 1901; A. 

 attenuate, Rydb. 1. c. 32: 136. 1905.) In the foothills; Wyoming and Colo- 

 rado. 



2. Troximon villosum (Rydb.) A. Nels. Leaves oblanceolate, more or less 

 pubescent, especially on the margins and veins; scape 1-2 dm. high, often 

 sparingly hairy and villous under the head: involucre campanulate, about 2 

 cm. high; outer bracts ovate or ovate-lanceolate, more or less villous especially 

 on the margins, dotted with blackish dots; inner bracts lanceolate: ligules 

 yellow or the outer tinged with reddish: achenes with a short striate beak. 

 (Agoseris villosa Rydb. Mem. N. Y. Bot. Gard. 1: 458. 1900; A. maculata 

 Rydb. Bull. Torr. Club 32: 136, 1905, the original description of which is 

 here used.) Colorado to Montana. 



3. Troximon glaucum Nutt. Gen. 2: 128. 1818. Perennial, pale or glau- 

 cous, glabrous throughout or a little woolly below: leaves linear, lanceolate, 

 or oblong, entire, dentate, or pinnatifid, 5-25 cm. long, 4-20 mm. wide, acu- 

 minate at the apex, narrowed at the base, sometimes into margined petioles: 

 scapes stout, glabrous or slightly pubescent, longer than the leaves, often 

 4 dm. high: involucre oblong-campanulate, or broader in fruit, commonly 

 quite glabrous, the bracts lanceolate, acuminate: achenes conspicuously 

 beaked; pappus of rather rigid, scabrous or denticulate bristles. (T. roseum 

 Nutt. Trans. Am. Phil. Soc. 7: 434. 1841; see also Greene, Pitt. 2: 77 & 176. 



