90 EEYTHEA. 



■ward to the crest of tlie Sierra Nevada, while others reach 

 far southward into Texas and Mexico, and some to the bluffs 

 of the Pacific seaboard in California. Of the Appalachian 

 series the most highly differentiated types have an herbage 

 silvery with a dense silky-flaky pubescence, and achenes 

 somewhat fusiform and even rostrate-attenuate. Two dis- 

 tinguished specialists, Nuttall and Schultze have, independ- 

 ently, proposed for this type the rank of a genus. Nuttall 

 named and defined them as species of Pifyopsis^ and Schultze 

 had his Heyfeldera out of this group. These plants, I would 

 remark in passing, are quite intimately connected with Aster 

 through that subdivision which contains A, concolorj so 

 intimately, that I venture to say the more branching state of 

 that species would have been made a Chrysopsis without hesi- 

 tation, by any author, if only the flowers had been yellow 

 instead of purple. * 



The far-western series of species differs from the Appala- 

 chian series in habit slightly, and more notably in the posses- 

 sion of a coarser pubescence, and this often of two kinds, 

 hirsute and pilose, or in some instances almost hispid. 



The territory occupied by this far-western, or Eocky 

 Mountain series is, at the very lowest estimate, four times 

 greater than that over which the Appalachian species are 

 disseminated, and embraces incalculably greater diversity of 

 soils and climates; yet, according to the most recent estimate 

 of the whole number of species of true Chrysopsis, those of 

 the limited eastern range considerably exceed those of the 

 vastly more extensive western one. 



If the genus were a particularly near ally of typical Aster 

 and Solidago such inequality of distribution would not be 

 remarkable; for those genera belong in a special manner to 

 the Appalachian flora, where their species twice outnumber 

 those of the far West. But the real affinities of Chrysopsis 

 are with Macronema, Pyrrocoma, Stenohts and other genera 

 which, like these, are not represented in the Appalachian 

 region. Hence, without doubt, the largest development of 

 Chrysopsis will be found on the western side of the conti- 



