AND GENERA. OF PLANTS. 301 



Hab. Arid plains towards the sources of the Platte. Rays short, pale purple, obscurely toothed, 

 almost entire. Nearly allied to the preceding. Scales of the involucrum about three series, acute. 



Dieteria ^ divaricata; pulverulently pubescent, radical leaves spathulate or 

 lanceolate, repandly and incisely serrate, above smaller, linear, sessile and 

 nearly entire; stem divaricate, branchlets subraceraose, or one or two flowered, 

 fastigiate; sepals about four series, reflected; rays twelve to sixteen, about as 

 long as the disk. 



Hab. Denudated plains of the Rocky Mountains, and Oregon, common. Rays short, pale blue 

 or purple. Pappus fulvous or white, (the white shorter and less copious, perhaps the mark of a 

 different species ;) branches rather naked, with small leaves spreading out into a compound corymb. 

 About a foot high. 



Dieteria * viscosa; pulverulently pubescent, and more or less glandular and 

 viscid; leaves all linear or lanceolate-linear, pinnatifidly or incisely serrate, acu- 

 minate, uppermost entire, sessile; stems simple, racemosely and corymbosely 

 branched; scales of the involucrum acute, reflected at the tips, imbricated 

 closely and equally in about five series; rays eighteen to twenty, about as long 

 as the disk. 



Hab. With the above, particularly near Scott's Bluff, on the Platte. Rays longer than in the 

 preceding, purple. Stem simple, attenuated, often very viscid, and exhaling the strong, heavy 

 scent of Jlster graveolens or Gnaphalium Amencanura. Scales of the involucrum very numerous, 

 lanceolate, acute. Leaves sometimes nearly pinnatifid or runcinate. Pappus fulvous, that of the 

 discal florets about thirty-five to forty unequal rays, that of the radial female florets much shorter, 

 of about twenty-four rays. 



Dieteria * sessili flora; viscidly pubescent; stem simple, flowers sessile, in ax- 

 illary and terminal clusters ; leaves linear or sublanceolate, incise or subpinna- 

 tifid, acutely acuminate, sessile; sepals in about four series; rays ochroleiicous, 

 twelve to fifteen, about the length of the disk. 



Hab. With the above. About a foot high, stem mostly unbranched, scales of the involucrum 

 very glutinous. Nearly allied to Aplopappus spinulosus, (Decand.) to which_X-appliedJhe^name_ 

 qf^c?eranifi^sjji Fraser^c^logi^ ; that plant is, however, perennial. Closely allied to the pre- 

 ceding species, but differing much in the pale yellow rays; the pappus of the rays is, also, nearly 

 equal with that of the discal florets. Flowers smaller than in any of the preceding. 



1 1 Root perennial Flowers wholly yellow. (Sideranthus.) 

 Dieteria spinulosa. Aplopapypus spinulosus. Decand. Vol. V., p. 347. This spe- 



VII. — 4 A 



