THISTLE FAMILY 899 



VI. DECUMBEXTES. 



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

 Leaves 3-nerved, at least at the base, equally long-acuminate 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. ELATIORES. 



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



Bracts sparingly villous; leaves usually dentate. 



Ligules white; bracts scarcely squarrose; stem sparingly pubescent. 



43. E. Coulteri. 

 Ligules blue or purple; bracts squarrose; stem densely pubescent above. 



44. E. peregrinus. 



VIII. SALSUGIXOSI. 



Rootstock thick; leaves thickish, acute; bracts narrowly linear-lanceolate, with strongly 



spreading tips. 

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



45. E. salsuginosus. 

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



49. E. eucephaloides. 



Rootstock slender; leaves thin, with long mucronate tips; bracts narrowly linear-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 ciliate 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. 



Leaves 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-ciliate. 50. E. macranthus. 



Bracts linear, more or less hirsute. 



Stem and leaves glabrous or nearly so; the latter ciliate 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. 52. E. subirinervis. 



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

 nerved. 54. E. incanescens. 

 Leaves glandular-puberulent. 55. E. Vreelandii. 



X. GLABELLI. 



Involucre hirsute or strigose, not at all glandular. 



Leaves glabrous, except the ciliate 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 ciliate margins. 



Stem pubescent, especially above, only slightly glandular. 



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



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



with a single head. 59. E. rubicundus. 



Involucre slightly 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 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. 

 XL PHILADELPHICI. 



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

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



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

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



XII. ASPERI. 

 Pubescence short, usually not dense. 



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



