40 BULLETIN UNITED STATES GEOLOGICAL SURVEY. [VolYL 



Eocky Mountain region, although a few species of the latter reach the 

 Pacific, while the original one belongs to the Atlantic coast. Grindelia 

 and Gutierrezia are equally characteristic over the plains and quite over 

 to the Pacific, and both are sparingly represented in extratropical South 

 America. Lessingia, Coretlirogyne, and Fentachceta are peculiarly Gali- 

 fornian. Boltonia and the BelUs integrifoUa are peculiarly Atlantic. 

 Baccharis, with an immense development in South America and Mexico, 

 has penetrated northward on both coasts to about latitude 41°, eastward 

 in a single, westward in very few species. 



Inuloide^. — Are sparingly represented in America, and mostly in 

 the Gnaphalineous type. They are particularly few in the Atlantic flora, 

 and increase in number and diversification westward. 



Helianthoide^. — On the contrary, are mostly American, and 

 largely North American. Here are almost all the true species of Reli- 

 anthus, the perennials mainly Atlantic, the annuals more western. The 

 Atlantic flora is characterized by Silpliium^ Chrysogonum, Tetragonotheca, 

 Echinacea, and the greater part of BudbecTcia and Coreopsis, and it alone 

 has a Reliopsis ; the eastern i)lains have Thelesperma (more developed 

 farther- south, and reproduced in Buenos Ayres!), Ungelmannia, most of 

 Berlandiera, &c. ; the Eocky Mountains, Balsamorrhiza, Wyethia, Kelian- 

 tliella, &c., which they share with the Pacific flora; the latter repro- 

 duces the Coreopsoid type in Leptosyne and Pugiopappns. 



Galinsoge^ and Madie^. — Being exclusively American (and Ha- 

 waiian), and more related to the following than to the preceding tribe, de- 

 serve separate mention. Baldwinia and Marsliallia are peculiar to the 

 Atlantic flora; Blepharipappns to the Pacific. The rest' are Madiece, 

 and are specially characteristic of our Pacific flora — are peculiar to it, 

 indeed, except for the two Hawaiian Island genera, for the extension of 

 the common Madia into Chili, and for the eastward extension of some 

 species iuto the plains. Madia, Layia, and Hemizonia, in numerous spe- 

 cies, many of them showy, are predominant Compositse in California. 



Helenioideje (including the groups assigned to this tribe by Ben- 

 tham). — Are specially American, are few in the Atlantic flora (where the 

 few representatives are all of western types), are more numerous and 

 characteristic in and towards the Eocky Mountains, while beyond them, 

 as well as south of them and on the Pacific coa st, they attain their fullest 

 development. We will not enumerate the numerous mostly endemic 

 genera. 



Anthemideje. — Chiefly of the Old World ; would be most insignifi- 

 cant in North America except for the number of naturalized weeds and 

 for the ] emarkable development of sijecies and individuals of Artemisia, 

 especially of those which compose the Sage-brush on either side of the 

 Eocky Mountains. These have already been spoken of. For anything 

 like this development, as well as of the Chenopodiacese, which accom- 

 pany the Wormwoods, only corresponding parts of Northern Asia can 

 be looked to. 



