1002 CARDUACEAE 



2. T. canescens DC. A shrub, 3-10 dm. high; branches canescent, leafy; 

 leaves not fascicled, narrowly linear, straight or nearly so, 2-3 cm. long, 1-2 mm. 

 broad, white-tomentose ; heads about 15 mm. high; bracts 4, linear-oblong, ob- 

 tusish, canescent, slightly carinate; achenes densely silky-hirsute. Dry hill- 

 sides: Calif.— Utah— Ida.^B.C. Son. Je-S. 



_ 3. T. linearis llydb. A low, unarmed shrub; bark of the older stems shin- 

 ing and flaky; leaves linear, white-tomentose, somewhat keeled; bracts of the 

 mvolucre oblong, acute, white-tomentose, about 8 mm. long; achenes hirsute- 

 viUous. Dry hiUs: Utah— Colo. Son. Jl-Au. 



4. T. glabrata A. Gray. Shrub, 3-10 dm. high; primary leaves 6-15 mm. 



long; secondary ones narrowly linear, spatulate, fleshy, 4^10 mm. long; heads 



about 12 mm. high; involucres cylindric, 6-7 mm. high, 4 mm. broad, silky- 



tomentose; achenes densely silky-hirsute. Dry hills: Ore.— Ida.— Utah— Calif. 

 Son. Je-Au. 



5. T. Nuttallii T. & G. Shrub, 3-10 dm. high; primary leaves transformed 

 into spreadmg subulate spines, 10-18 mm. long; secondary leaves oblanceolate, 

 8-12 mm. long, loosely floccose; heads 10-14 mm. high, fascicled-corymbose; invo- 

 lucres 7-8 mm. high, tomentose; bracts 4, linear-oblong; achenes densely white- 

 hoary. Barren hills: Wyo.— Utah. San.—Submont. My-Au. 



^ 6. T. spinosa Hook. & Arn. A divaricately branched shrub, 5-12 dm. high; 

 branches white-tomentose; primary leaves transformed into spines, 5-12 mm 

 long, usually more or less curved; secondary leaves 5-15 mm. long, linear-clavate, 

 fleshy, glabrous or soon glabrate; heads from the axil of the leaves, 15-18 mm. 

 high; involucres tomentose, about 1 cm. high; bracts oval, obtuse, or some of 

 them acutish. Dry hills and plains: ^^lont.— Colo.— Nev.— Ore. PlainSub- 



mont. My-Au. 



7. T. longispina (M. E. Jones) Rydb. Shrub, 1-2 m. high; branches di- 

 varicate, tomentose; primary leaves transformed into slender, straight spines, 

 1.5^3 cm. long; secondary leaves linear-clavate, 10-12 mm. long, glabrate; heads 

 sobtarj' m the axils of the leaves, 12-15 mm. high; involucres about 6 mm. high 

 tomentose; bracts elliptic; achenes with long white hairs equalhng the paimus 

 1. smnosa longispina M. E. Jones. AlkaUne hills: Utah— Ariz.— CaUf. Son 



Ap-Jl. 



131. ARCTIUM L. Burdock. 



Coarse biennial herbs. Leaves airernate, petioled, with broad cordate or 

 sagittate blades. Heads discoid. Involucres globular; bracts imbricate, in 

 many series, subulate, with hooked tips. Receptacle flat, setose. Flowers 

 hermaphrodite and fertile. Corolla purple or white; tube slender. Anthers 

 sagittate at the base. Achenes oblong, somewhat compressed and 3-angled 

 truncate. Pappus of numerous short and rigid bristles, falling off separate. 



T^x-^feS^i^f ^^^'^K ^ *^,™- broad; inner bracts not exceeding the flowers. 1. A. minus. 

 ln^ olucre 2.5 cm. broad or more ; inner bracts at least equalling the flowers. 2. A. Lappa. 



. , ^ ^f^\^^- ^^i^™ ^*'^,^*' ^"-0 d™- high' puberulent, branched; 

 leaves petioled; blades 2-4 cm. long, cordate, repand. grayish tomentulose 

 beneath; heads in a leafy panicle, often with racemiform branches; involucres 

 12-20 mm. high^ glabrous ; the mner bracts purple-tipped; coroUas rose-purple. 

 fro^Eu^'Tu-^ ^^ ^ '' -^'■^•-^^•— Ala.-Colo.-Ida.— B.C.; nat. 



tK \ ^' ^*?P* ^1- ^^^"^ ^^2 m. high; leaf-blades thin, broadly ovate-cordate, 

 the lower 4-5 cm. long, grayish tomentose beneath; heads corjTnbose; involucre 

 g abrous or nearly so; bracts longer and more spreading or reflexed; corollas rose- 

 ^ j\-0 ^ N.B.-N.Y.-Neb.— Minn.; Mont.; nat. or adv. from 



132. SAUSSUREA DC. 



minus 



Perennial herbs. Leaves 



cose. Heads discoid many-flowered. Involucre usually narrow, turbinate ; bracts 

 imbricate in several series. Receptacle flat, fimhrniatp nr nh^ff^r n^.r^AU. 



fimbrillate or chaffy. Corollas 



