45 



numerable subdivisions and many peculiar species. There are the 

 Chihuahua plains, the Yaqui-Sonora region on the floor, and •.':i the 

 high plateaus are many valleys and mountain ranges with interest- 

 ing floras. The most imi)ortant are Sierra Madre plateau, the Coa- 

 huila ranges, the Mt. Colima region, the Valley of Mexico and simi- 

 lar valleys of central Mexico, Popocatapetl, the San Luis Potosi re- 

 gion, the Lake Chapala region, and others. 



Passing from the floor of the Great Plateau we find far less 

 species differentiation, but almost every range of mountains has a 

 distinctive flora more or less separate from any other. The Colora- 

 do Rocky Mountains are interesting and include the Yellowstone on 

 the north and New Mexican on the South to Santa Fe. There is the 

 Glacier Park region of Montana, the Blue Mountains of Oregon, the 

 Sawtooth and Bitterroots of Idaho and Montana, the Wasatch and 

 Uintas of Utah, the Deei) Creek in western Utah, the Schell Creeks 

 and Clover mountains of eastern Nevada and the West Humboldts 

 of western Nevada, and also the Malheur range, the Pioche region, 

 the Charleston peaks, the Funeral and Panamint mountains, the Pro- 

 vidence range, the White mountains of California, the Cascades, the 

 Coast range, the Sierras, the San Bernardinos, the San Jacintos, San 

 Pedro Martir, Mogollons, Sandias. Catalinas, Santa Ritas, Chiricahuas, 

 Huachucas, Floritas, and several ranges in western Texas. It would 

 be too tedious to go into the floras of each, and in addition they are 

 only local and feather into the adjoining regions. 



The distribution of Astragalus at the far north has nothing 

 of importance. A few species range throughout the forest region to 

 the tundras of the Arctic. There are no distinct floral regions worthy 

 of note beyond the Saskatchewan, nor has the Atlantic region any 

 significance beyond the usual life zone limits. The peaks of New Eng- 

 land have a few alpine and high latitude species. 



