326 RYDBERG: PHYTOGEOGRAPHICAL NOTES 
Cascades alone, and less than 2 per cent in the Sierra Nevada 
alone. If the transcontinental plants are added, the percentage 
for the plants found in both the Sierras and the Cascades and for 
those found in the Cascades alone would be increased to about 20 
per cent of each. The ratio for those found in the Sierras alone 
would remain less than 2 per cent. This refers of course to the 
Montane plants only. In the Submontane region the ratio would 
be much greater. 
The endemic element consists of 1,046 Montane plants or 
over 53 per cent of the whole number. Of these, 245 or nearly 
13 per cent are common to the Northern and Southern Rockies, 
560 or nearly 29 per cent being restricted to the Southern Rockies, 
and 230 or 12 percent to the Northern. Of the latter about 10 per 
cent extend as far south as Northern Wyoming and I per cent are 
restricted to the Canadian Rockies. Of the species restricted to 
the Southern Rockies over 11 per cent are common to the Main 
Range in Wyoming, Colorado, and New Mexico and the Uintah- 
Wasatch region, while 13% per cent are restricted to the former and 
nearly 4 per cent to the latter. Of those restricted to the Northern 
Rockies, 8 per cent are found in Northern Wyoming and a little 
over I per cent are restricted to the Canadian Rockies. If the 
flora of the Canadian Rockies were better known this latter number 
probably would be much larger. We must also remember that 
only the region south of latitude 55° is here considered. 
It may also be of interest to see how the number of species 
found in the Southern and Northern Rockies would compare, if 
all categories of Montane plants are taken in consideration. There 
are over 40 per cent common to both, nearly 28 per cent restricted 
to the Southern Rockies and 32 per cent to the Northern. The 
species found in the Southern but not in the Northern Rockies 
consist almost wholly of endemic forms, less than 2 per cent being 
common to the Southern Rockies (and most of these found only in 
Utah) and the Sierra Nevada and 3 species only being Eastern 
nontranscontinentals. Those found in the Northern Rockies and 
not in the Southern consist of over 3 per cent transcontinental 
species, less than 2 per cent being common to the Northern Rockies 
and the Eastern Canadian Zone, nearly 15 per cent common to 
the former and the Pacific Mountains and 12 per cent endemics: 
altogether 32 per cent of all Montane species. 
