586 coMPOsiTAE (composite family) 



1893. Stem simple, 4 dm. or less high, glabrous and leafy up to the heads, 

 which are terminally clustered: leaves obloiig or oblanceolate, deeply sinuate- 

 pinnatifid with spinulose lobes to nearly entire, somewhat arachnoid-wooUy, 

 especially beneath: involucre 3.5-4 cm. high; the bracts chalrtaceous, the 

 inner with weak scarious tips which vary from entire and acute to obviously 

 dilated and fimbriate, the outer gradually shorter and becoming ovate, the 

 tips acute and short-spinose: corollas white, the lobes not longer than the 

 throat: anthers very acuminate. (C. oreophilus Rydb. 1. c. 28: 609. 1901.) 

 — Mountain valleys of our range and far westward and northward. 



6a. Carduus Drummondii acaulescens (Gray) Coville, 1. c. Includes the 

 low forms of the species, in which the stem may be wholly wanting, and the 

 usually smaller heads sessile in the rosette of radical leaves. In the same 

 patch may often be found the normal form and all stages to the depressed 

 rosette type. (C. americanus Rydb. and C. acaviescens RydbJ 1. c. 508.) — 

 Mountain meadows; range of the species. 



7. Carduus bipinnatus (Eastw.) Heller, Cat. N. A. Plants 6. 1900. Gla- 

 brous except for some arachnoid tomentum; stems leafy, 3-7 dm. high, branch- 

 ing: leaves with numerous linear-lanceolate divisions which are 2-6 cm'. long, 

 margin laciniate-dentate, spiny; radical leaves petioMe, 2-3 dm. long; the cau- 

 line, sessile, 10-15 cm. long: heads at the ends of the leafy branches, almost 

 sessile; involucre of appressed, imbricated bratts, in several ranks succes- 

 sively shorter, the lower ones pointed with a weak prickle, the upper atten- 

 uate to a scarious tip, puberulent: flowers purple; corolla with throat about 

 one third as long as the linear divisions: stamens surpassing the corolla: 

 achenes glabrous, flattened, obovate^oblong. [C. pidchella and C. truncaius 

 Greene (?) ; C. spathiilaiits Osterh. 1. c.y—bi mountain parks; Colorado. 



8. Carduus neo-mexicanus (Gray) Greene, 1. c. Stout j 5-10 dm. high; 

 herbage and commonly squarrose mvolucre copiously whit&-woolly: leaves 

 sinuate-dentate to pinnatifid, not very prickly: heads solitary, terminating the 

 stem and branches, often 4-5 cm. high and broad; principal bracts of the in- 

 volucre with spinescent, rigid, reflexed tips, or the bracts m part reflexed: co- 

 rolla white to pale purple. ; (C. levcopsis Greene.) — Plains of Colorado and 

 New Mexico to Utah and Arizona. 



9. Carduus lanceolatus L. Sp. PI. 821. 1753. Stems stout, 4-10 dm. 

 high, much-branched, more or less viUous-hirsute: leaves lanceolate, deeply 

 pinnatifid with lanceolate lobes, rigidly prickfy, upper face strigose-setulose; 

 the base decurrent on 'the stem into interrupted prickly wings: heads obovoid, 

 3-5 cm. high, terminating the stems and branches; bracts of the' involucre 

 arachnoid-woolly, lanceolate and mostly attenuate into slender, spreading 

 spines: corollas rose-purple. — Pastures and waste pla,ces throughout the 

 northern United States; natm-alized from Em-ope; Common Thistle or often 

 called Bttll Thistle. 



10. Carduus NeJsonii Pammel, Proc. Iowa Acad. Sci. 8: 22. 1901. A 

 branching biennial, '4-10 dm. high, bearing numerous ochroleucous heads, 

 which terminate tbS branches; stems prominently striate, white-woolly at 

 first, becoming smoothish with age: radical leaves 1-3 dm. long, deeply pin^ 

 natifid, the prominent lobes with yellow spines; lower surface densely tomen- 

 tose; the upper woolly, becoming glabrate with age; stem leaves sessile and 

 decurrent, with prominent spiny lobes: heads 3-4 cm. high, or rarely larger | 

 involucre somewhat turbjhate, the bracts with a prominent glutinous ridge 

 tipped with a yellow spine ; outer bracts ovate-lanceolate ; inher long-acuminate 

 and straw-colored, tips minutely serrated: corolla-tube twice as long as the 

 lobes, strongly clavate: anther-tips acute, bases sagittate; filaments hairy: 

 achene light brown throughout, with dark longitudinal striae; pappus Of 

 outer flowers merely barbellate, inner plumose with strOngly clavate tips. 

 (C. Traa/i Rydb. 1. c. 32: 133. 1905.)— Frequent on the plains of Wyominc^; 

 probably more widely distributed. 



11. Carduus plattensis Rydb. Contr. U. S. Nat. Herb. 3: 167. pi. 2. 1895. 

 Perennial or biennial, the root thick and deep-set; stem stout, simple, or little 

 branched, 4-7 dm. high, densely white-felted: leaves deeply pinnatifid, white- 



