THISTLE FAMILY 909 



small, linear; heads solitary; involucres 8-10 mm. high, 15-20 mm. broad, stri- 

 gose; rays white, 8-10 mm. long. W. argentata A. Nels. Arid regions: Mont. 

 w Colo. Utah Nev. Plain Son. Je-Jl. 



79. E. canus A. Gray. Stem decumbent at the base, 1-2 dm. high, stri- 

 gose-canescent; basal leaves narrowly linear-oblanceolate, 1^4 cm. long, canescent- 

 strigose; stem-leaves narrowly linear; heads solitary; involucres 5-6 mm. high, 

 10-12 mm. broad; bracts lanceolate-linear, acute; ligules purplish or white, 6 

 mm. long. W. cana A. Nels. Dry plains and ridges: S.D. Neb. N.M. Wyo. 

 Plain Mont. Jl-Au. 



80. E. corymbosus Nutt. Stem 1-4 dm. high, corymbosely branched above, 

 short-hirsutulous; basal leaves narrowly linear-oblanceolate, 3-nerved, 5-15 cm. 

 long, densely hirsutulous; stem-leaves linear; involucres 5 mm. high, 8-12 mm. 

 broad; bracts hirsute; ligules lilac or purplish, rarely white, 30-50, about 8 mm. 

 long. E. Nelsonii Greene. Plains: Mont. Wyo. Calif. B.C. Plain. Je- 

 Au. 



81. E. subcanescens Rydb. Stem erect, canescent-hirsutulous; basal 

 leaves linear-oblanceolate, mostly obtuse, 6-10 cm. long, triple-nerved, densely 

 canescent; involucres 5 mm. high, 10-12 mm. broad; bracts linear, acute, canes- 

 cent-hirsutulous; ligules white or rarely pinkish, about 8 mm. long. E. caespi- 

 tosus laccolilicus M. E. Jones. Stony slopes and plains: Sask. Colo. Utah 

 B.C. Plain. Jl-Au. 



82. E. caespitosus Nutt. Stem 1-1.5 dm. high, canescent; basal leaves 

 oblanceolate, 5-10 cm. long, less distinctly 3-nerved, obtuse, densely hirsutulous- 

 canescent; involucre 6-7 mm. high, 10-15 mm. wide; bracts linear, hirsute-canes- 

 cent, acute; ligules 40-50, white, 7-10 mm. long. Dry hills and plains: Sask. 

 Colo. Utah Yukon. Plain Mont. Jl-Au. 



83. E. nauseosus (M. E. Jones) A. Nels. Stem 1-1.5 dm. high, glandular- 

 puberulent; basal leaves with winged petioles, 3-5 cm. long, spatulate, 3-nerved, 

 glandular-puberulent and ciliate on the margins; stem-leaves spatulate or elliptic, 

 sessile; heads solitary; involucres about 6 mm. high, 12-15 mm. wide; ligules 

 white, 8-10 mm. long, 1 mm. wide. E. caespitosus nauseosus Jones. Hillsides: 

 Utah. Submont. Je. 



84. E. nevadensis A. Gray. Stem 1-3 dm. high, strigose-canescent; basal 

 leaves narrowly linear-oblanceolate, 3-nerved, canescent, 5-10 mm. long; stem- 

 leaves linear; heads solitary; involucres about 7 mm. high, 12-18 mm. broad, 

 much shorter than the flowers; ligules white or pale blue, 8-12 mm. long. Dry 

 hills and mountains: Utah Nev. Calif. Submont. My-Jl. 



85. E. Eatonii A. Gray. Stem 1 dm. high or less, strigose; basal leaves 

 narrowly linear-oblanceolate or linear, 3-nerved, strigose, 5-10 cm. long, 1-4 

 mm. broad; stem-leaves narrowly linear, often falcate; heads usually solitary; 

 involucres 5-6 mm. high, 7-10 mm. broad; bracts rather few, linear, in about 3 

 series, but only slightly imbricate; ligules about 20, purplish or white, 6-7 mm. 

 long. Mountains: Utah Wyo. Ore. Submont. Mont. Jl-Au. 



86. E. asperugineus (D. C. Eat.) A. Gray. Perennial, with a cespitose woody 

 caudex; stem monocephalous, less than 1 dm. high, hirsutulous-canescent; basal 

 leaves thick, spatulate, petioled, 1-3 cm. long, densely hirsutulous-canescent; 

 stem-leaves small, oblong or oblanceolate; involucres 56 mm. high, 10-12 mm. 

 broad, hirsute; bracts linear, slightly imbricate; ligules about 20, bluish or purple, 

 about 8 mm. long. E. elkoensis Nels. & Macbr. Dry hills and mountains: 

 Mont. Wyo. Nev. Submont. Mont. Jl-Au. 



87. E. Tweedyi Canby. Stem scapiform, 5-15 cm. long, canescent-stri- 

 gose; basal leaves 2-5 cm. long, oval or obovate-spatulate, thick, silvery-canes- 

 cent; stem-leaves few and small, linear-oblanceolate; heads solitary, or rarely 2 

 or 3; involucres 5-6 mm. high, 12-15 mm. broad; ligules purple, 5-7 mm. long. 

 Dry mountains and hillsides: Mont. Wyo. Mont. Subalp. Je-Au. 



88. E. tener A. Gray. Stem scapiform, 5-10 cm. long, strigose; basal 

 leaves oblanceolate or spatulate, petioled, 2-4 cm. long, rather sparingly strigose; 

 stem-leaves small and linear; heads solitary or rarely 2 or 3; involucres 4-5 mm. 



