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GENUS CHRYSOTHAMNUS. 



Taxonomically, this is the type species of the genus, since it was the first one published 

 by Nuttall under his new genus, Chrysothammis, in 1841. It was antedated, however, by 

 Hooker's Crinitaria viscidiflora, so that this specific name takes precedence when the two 

 are united into one major species. 



Fio. 26. — Phylogenetic chart of the subspecies of Chrysoth 



viecidifioruB. 



The next group centers around subspecies puberulus, through which they are connected 

 with lanceolatus. All are characterized by a peculiarly pale, usually grayish or yellowish- 

 green herbage, although this feature is not sufficiently constant to be dependable in 

 taxonomic work. They are most plentiful in the Great Basin area. Puberulus has 

 given rise, perhaps by mutation as already noted, to the glabrous sienophyllus and by 

 gradual variation to humilis. This latter is a reduced far-western type of high altitudes. 

 While its distinguishing characters do not seem to possess much taxonomic value, yet 

 the appearance of the plants is so unlike that it seems best to retain the form, at least 

 provisionally, as a distinct subspecies. 



