586 COMPOSITAE (COMPOSITE FAMILY) 



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

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

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

 especially beneath: involucre 3.5-4 cm. high; the bracts chartaceous, 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: 509. 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. acaulescens Rydb. 1. c. 508.) 

 Mountain meadows; range of the species. 



7. Carduus bipinnatus (Eastw.) Heller, Cat. N. A. Plants 5. 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 petiolate, 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 bracts, 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. pulchella and C. truncatus 

 Greene (?); C. spathulatus Osterh. 1. c.] In mountain parks; Colorado. 



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

 herbage and commonly squarrose involucre copiously white-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 in part reflexed : co- 

 rolla white to pale purple. (C. leucopsis Greene.) Plains of Colorado and 

 New Mexico to Utah and Arizona. 



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

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

 pinnatifid with lanceolate lobes, rigidly prickly, 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 places throughout the 

 northern United States; naturalized from Europe; COMMON THISTLE or often 

 called BULL THISTLE. 



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

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

 which terminate the 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 turbinate, the bracts with a prominent glutinous ridge 

 tipped with a yellow spine; outer bracts ovate-lanceolate; inner 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. Tracyi Rydb. 1. c. 32: 133. 1905.) Frequent on the plains of Wyoming; 

 probably more widely distributed. 



11. Carduus plattensis Rydb. Contr. U. S. Nat. Herb. 3: 167. pi. 2. lS!)f>. 

 Perennial or biennial, the root thick and deep-set; stem stout, simple, or lid K> 

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



