THISTLE FAMILY 249 



Involucre conspicuously hirsute as well as glandular; stem low, usually 



with a single head. 50. E. rubicundus. 



Involucre sUghtly if at all hirsute; stem 3 dm. high or more, usually with 

 more than one head. 60. E. eximius. 



Bracts lance-subulate; ligules white. 43. E. Coulteri. 



Stem scarcely hairy, decidedly glandular above. 61. E. Smithii. 



Leaves and steni more or less pubescent. 



Involucres about 18 mm. broad; plant conspicuously long-hairy. 



62. E. formosissimus 

 Involucres about 15 mm. broad; plant less conspicuously hairy, more glandular. 



63. E. viscidus. 

 VCI. Phil.\delphici. 



Basal leaves crenate or dentate, with broad rotmded or ovate teeth; upper leaves lanceo- 

 late, acute; rays white or pink. 64. E. philadelphicus. 



Basal leaves dentate, with sharp, triangular, saUent teeth; upper stem-leaves triangular- 

 lanceolate, acuminate; rays rose-colored or purple. 65. E. purpureus. 



XII. ASPERI. 



Pubescence short, usually not dense. 



Pubescence apjiressed or rarely spreading; hairs not with pustulate bases. 



Heads small; disk 1 cm. or less wide; ligules white; basal leaves linear-oblanceolate. 



entire. 66. E. nsper. 



Heads larger; disk 1-1.5 cm. wide; ligules blue or purple; basal leaves usually more 

 or less toothed, oblanceolate. 67. E. oblanceolalus. 



Pubescence spreading ; hairs with pustulate bases ; basal leaves narrowly oblanceolate ; 

 ligules white or rarely pale rose. 68. E. c'onsobrinus. 



Pubescence long, dense, spreading or reflexed. 69. E. Drurmnondii. 



XIII. Ramosi. 

 One species. 70. E. rainosus. 



XIV. Beli.idiastra. 



One species. Tl. E. Bellidiastrum. 



XV. DiVERGENTES. 



Stem simple below; rays usually wliite. 72. E. Wooloni. 



Stem branched at the base; rays usually purplish. 73. E. divcrgens. 



XVI. Fl.\geli.ares. 



Leaves and stems appressed-hairy. 74. E. flagellaris. 



Leaves and stem densely short-pubescent with spreading hairs. 



Basal leaves oblanceolate, entire, or 3-lobed at the apex; leaves of the stolons linear; 



plant gray. 75. E. commixtus. 



Basal leaves obovate-spatulate, entire, or with several lateral lobes or teeth; leaves 

 of the -Stolons oblanceolate; plant greener. 76. E. nudiflorus. 



XVII. Cani. 

 Disk of the heads fully 1 cm. high and about 1.5 cm. wide; basal leaves spatulate, obtuse. 



Leaves canescent. 77. E. Wyomingia. 



Leaves silvery white. 78. E. argentalus. 



Disk of the heads 7-8 mm. high and about 1 cm. wide; ba.sal leaves oblanceolate, mostly 



acutish. 79. E. canus. 



XVIII. C.^ESPITOSI. 



Stem leafy; stem-leaves almost as broad as the basal ones. 



Lower leaves narrowly Unear-oblanceolate ; upper leaves narrowly linear; all acute 



and coarsely hairy; rays usually hlac or purphsh. 80. E. corymbosus. 



Lower leaves oblanceolate or linear-spatulate, usually obtusish; stem-leaves hnear 

 or oblong; all densely canescent; rays usually wliite. 

 Stem erect, about 3 dm. high, usually with several heads; stem-leaves linear. 



81. E. subcanescens. 

 Stem decumbent at the base, 1-2 dm. liigh, with 1-3 (seldom more) heads; stem- 

 leaves oblong. 

 Plant not conspicuously glandular. 82. E. caespitosus. 



Plant conspicuously glandular. 83. E. nauseosus. 



Stem more or less naked above, decumbent at the base; stem-leaves at least the upper 

 ones reduced. 

 Stems about 2 dm. high; disk 10-12 mm. high and about 15 mm. wide. 



84. E. nevadensis. 

 Stems about 1 dm. high; disks about 6 mm. high and less than 1 cm. wide. 



85. E. Eatonii. 



XIX. ASPERUGINEI. 



Leaves with a spreading rough pubescence. 86. E. asperugineus. 



Leaves strictly appressed-cinereous. 



Disk 10-15 mm. wide; leaves finely and densely hairy; involucral bracts strigose. 



87. E. Tu-cedyi. 

 Disk 5-10 mm. wide; leaves sparingly and coarsely hairy; involucral bracts hirsute 

 and glandular-puberulent. 88. E. tener. 



XX. Arenarioides. 



One species. 89. E. arenarioides. 



XXI. LAETEVIRENTE.S. 



Stems 1 .5-2 dm. high, leafy. 



Ligules blue or purple, scarcely more than 1 mm. wide. 90. E. laetevirrns 



