40 BULLETIN UNITED STATES GEOLOGICAL SURVEY. [Vol.VL 



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

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

 and Guticrrczia are equally characteristic over the plains and quite over 

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

 America. Lessingia, Corethrogyne, and Pentachceta are peculiarly Cali- 

 fornian. Bolton la and the Belli s integrifolia 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^e. — 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 Heli- 

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

 Atlantic flora is characterized by Silphitim. Chrysogonum, Tetragonotlieca, 

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

 has a Heliopsis ; the eastern plains have Thelesperma (more developed 

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

 Berlandiera, &c. ; the Rocky Mountains, Bahama rrhiza, Wyethia, Helian- 

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

 duces the Coreopsoid type in Leptosyne and Pugiopappns. 



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

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

 serve separate mention. Bahhcinia and Marshallia are peculiar to the 

 Atlantic flora; Blepharipappus 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 into the plains. Madia, Layia, and Hemizonia, in numerous spe- 

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



Helenioide^e (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 Rocky Mountains, while beyond them, 

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

 development We will not enumerate the numerous mostly endemic 

 genera. 



Anthem ii>K. I-:.— Chiefly of the Old World; would be most insignifi- 

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

 for the remarkable development of species and individuals of Artemisia^ 



('specially of those which compose the Sagebrush on either side of the 

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

 like this development, as well as of the Cheuopodiacea?, which accom- 

 pany the Wormwoods, only corresponding parts of Northern Asia can 

 be looked to. 



