THISTLE FAMILY 899 



VI. DKCinMBEXTES. 



Leaves 1-nerved, linear-oblanceolate; the lower iLsually obtusish. 26. E. Engelmannii. 

 Leaves 3-nerved, at least at the base, equally loriK-acuniinate at both ends. 



Pubescence of the leaves loose, hirsute and somewhat glandular-puberulent. 



40. E. decumbens. 



Pubescence of the leaves appressed-strigose. 41. E. microlonchus. 



VII. El.\tiores. 

 Bracts very densely •villous, squarrose; leaves entire. 42. E. elatior. 



Bracts sparingly ■villous; leavas usually dentate. 



Ligules white; bracts scarcely squarrose; stem sparingly pubescent. 



4.3. E. CouUeri. 

 Ligules blue or piu-ple; bracts squarrose; stem densely pubescent above. 



44. E. peregrinus. 

 VIII. Salsuginosi. 



Rootstock tliick; leaves thickish, acute; bracts narrowly Unear-lanceolate, with strongly 

 spreading tips. 

 Pedimcles mostly solitary, finely strigose; stem single from the rootstock. 



45. E. salsuginosus. 

 Peduncles usiially more than one, scabrous; stems several from a caudex. 



49. E. eucephaloides. 

 Rootstock slender; leaves thin, with long mucronate tips; bracts narrowly Unear-subu- 

 late, only slightly spreading. 46. E. Howellii. 



IX. Macranthi. 

 Basal leaf-blades broadly obovate-spatulate, often denticulate; stem-leaves distant, 

 shorter than the internodes, not cUiate on the margins; bracts glandular-puberulent, 

 seldom with a few hairs. 47. E. superbus. 



Basal leaf-blades oblanceolate, entire; stem-leaves usually longer than the internodes, 

 usually ciliate on the margins. 

 Bracts linear-subulate, glandular-puberulent, not at all hirsute; leaves glabrous. 

 Leaves linear-lanceolate, minutely ciliolate. 



Leavas dark green; bracts not with loose tips. 48. E. salicinus 



Leaves Light green; bract with spreading tips. 49. E. eucephaloides. 



Leaves not dark green, dull, strongly hirsute-ciUate. 50. E. macranthus. 



Bracts Linear, more or less hirsute. 



Stem and leaves glabrous or nearly so; the latter ciUate only on the margin and 

 the veins below; bracts glandular-puberulent and with scattered hairs. 



51. E. speciosus. 

 Stem and leaves hairy; bracts hirsute or both hirsute and glandular. 



Leaves hirsute. 



Pubescence scant, that of the stem long ; leaves linear-lanceolate. 



52. E. conspicuus. 

 Pubescence of the leaves and the involucres dense, that of the stem short. 



Plant tall, green; upper stem-leaves ovate or ovate-lanceolate, dis- 

 tinctly triple-nerved. 5^ E. subtrinervis. 



Plant low, canescent; upper stem-leaves lanceolate, scarcely triple- 

 nerved. 54. E. incanescens. 

 Leaves glandular-puberulent. 55. E. Vreelanriii. 



X. Gl^\.BELLI. 



Involucre hirsute or strigose, not at aU glandular. 



Leaves glabrous, except the ciUate margins. 56. E. glabellus. 



Leaves more or less pubescent. 



Pubescence loose and spreading. 57. E. fruticetorum. 



Pubescence appressed. 58. E. Earlei. 



Involucres more or less glandular, sometimes also hirsute. 

 Leaves glabrous, except the ciUate margins. 



Stem pubescent, especially above, only slightly glandular. 



Bracts narrowly Unear-subulate ; ligules usually bluish or pink. 



Involucre conspicuously hirsute as well as glandular; stem low, usuaUj' 



with a single head. 59. E. rubicundus. 



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

 more than one head. 60. E. eximius. 



Bracts lance-subulate; Ugules white. 43. E. CouUeri. 



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



Leaves and stem 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. 



XI. PHIL.\DELPniCI. 



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

 late, acute; rays white or pink. G4. E. philadclphicus. 



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

 lanceolate, acuminate; rays rose-colored c5i^urple. 65. E. purpureus. 



XII. ASPERI. 



Pubescence short, usually not dense. 



Pubescence appressed" or rarely spreading ; hairs not with pustulate bases. 



