158 GENUS CHRYSOTHAMNUS. 



convey an erroneous idea as to their relationships, for it is quite certain that the true 

 Bigelovias and the Chrysothamni are not descendants of the same immediate stock and 

 that in each case there are more closely related genera to be considered. Some of these, 

 such as Petradoria, for example, may indeed come squarely between the two. The only 

 possible connection between Bigelovia and Chrysothamnus seems to lie in the only half- 

 shrubby C. gramineus. In addition to differing from Bigelovia in nearly all of the char- 

 acters just enumerated, this species has exceptionally long achenes even for a Chrysotham- 

 nus. If connected with the former genus at all, the relation would need to be sought 

 through Petradoria. Although Bigelovia was in use for more than 50 years, and even to 

 the present is occasionally so used as to include Chrysothamnus, the limits set for the genus 

 have been constantly moved about. Thus Gray, in 1873, enlarged it to include the sec- 

 tion Haplodiscus (Proc. Am. Acad. 8:638), a section now belonging to Haplopappus 

 section Isocoma, and in 1884 the same authority still further extended the boundaries to 

 include a portion of what now passes as Haplopappus section Ericameria (Gray, Syn. Fl. 

 P:141, 1884). This final extension left, as the only mark of distinction between Haplo- 

 pappus and Bigelovia, the presence of ray-flowers in the former and their absence in the 

 latter. This was obviously an artificial separation, as is evidenced by certain species, 

 such as H. monadis, H. arborescens, etc., in which the ray-flowers are either present or 

 absent even on the same plant. What now seems to be a more logical arrangement is 

 given farther on, the only object in mentioning these matters here being to call atten- 

 tion to the diverse conception of the limits set at various times for Bigelovia. 



Chrysothamnus was established as a genus by Nuttall in 1840 (Trans. Am. Phil. Soc. 

 II, 7:323) with C. pumilus as the type species. Chronologically it therefore follows 

 De CandoUe's Bigelovia by four years. This in turn was succeeded two years later by 

 Torrey and Gray's Flora, in which Bigelovia was restricted to the genuine herbaceous 

 species, while the species of Chrysothamnus were referred to Linosyris, a genus previously 

 considered as belonging only to the Old World. This usage was continued by Gray in 

 the Botany of the Mexican Boundary Survey, by D. C. Eaton in the Botany of the King 

 Expedition, and in a few other papers, until it was pointed out by Bentham and Hooker 

 (Genera Plantarum 2:255, 274, 1873) that Chrysothamnus was not of close affinity with 

 true Linosyris, the latter being better considered as a part of Aster. The former was thus 

 reestablished as a genus and extended to include the earlier Bigelovia of De CandoUe. 

 Gray readily accepted this arrangement (Proc. Am. Acad. 8:637, 1873), except that he 

 asserted the priority of the name Bigelovia, under which he renamed all of the species. 

 Bigelovia then came into general use. It was adopted by Bentham and Hooker (Genera 

 Plantarum 2:536, 1876) and was used by Gray in the Synoptical Flora and elsewhere. 



It thus transpired that between the spurious claims of Liyiosyris on the one hand and 

 of Bigelovia on the other, the generic name Chrysothamnus received but scant attention 

 until it was revived by Greene in 1895 (Erythea 3:92). Not only did Greene point out 

 the dubious status of the name Bigelovia, but he stoutly defended Nuttall's segregation 

 of Chrysothamnus from the herbaceous species which De Candolle took as the type of 

 that genus, without, however, hitting upon some of the more important distinctions as 

 above set forth. Greene's conception of the genus was adopted by Nelson in his paper, 

 "Some Rocky Mountain Chrysothamni" (Bot. Gaz. 28:369 to 377, 1899), and, with 

 some slight modifications, by nearly all of the writers of recent manuals in which, how- 

 ever, the number of recognized species has been steadily increasing. It is also the con- 

 cept adopted in the present paper, except that C. bloomeri (Gray) Greene is now referred 

 to Haplopappus and that two species here included were assigned to Ericameria by 

 Greene. It was characteristic of this author that, although he possessed a keen sense of 

 natural grouping, he seldom defined groups with any degree of precision. In the present 

 instance no generic diagnosis was given and, aside from the comparison with Chondro- 



