1913] HERRE—LICHENS OF MT. ROSE 303 
In part, at least, the absence of corticolous lichens is due directly 
to the winds of enormous velocity which are prevalent in this 
region. Gales of 50 miles an hour are frequent, while at times the 
inordinate velocity of 150 to 170 miles an hour is reached. As 
these winds sweep the mountain slopes, they carry sand or dust, 
sleet, and fine hard snow; the abrasive action of this flying material 
affects the bark of the conifers upon which it impinges in such a 
way that they appear as if freshly sandpapered. I was unable 
to find any indication of either lichens or mosses upon the bark of 
any tree or shrub examined. 
The dearth of earth lichens may be in part explained by other 
causes, such as excessive dryness, the erosive action of floods 
caused by the rapid melting of snow when the Chinook winds blow 
in early spring, etc. But as yet I cannot understand the failure 
to find any trace of such genera as Cladonia, Stereocaulon, Solorina, 
Cetraria, and similar genera containing species characteristic of 
alpine situations. Perhaps prolonged search in early summer just 
after the disappearance of the greater part of the snow would 
reveal some of them. 
The conditions noted above offer no hindrance to the growth of 
rock lichens. In the wooded slopes lichens occur on all rocks, but 
ms abundantly, even where not shaded by the pines. But at 
ooo ft. one comes suddenly into a region where lichens are both 
stieeese numerous and remarkably conspicuous. From 
here to the summit the dominant species is Gyrophora reticulata, 
which is excessively abundant; but the great bowlders strewing the 
mountain side and obstructing the trail are also spotted and 
blotched with huge, brilliant masses of Acarospora chlorophana, 
while Caloplaca elegans lends a gleam of fire to the somber landscape. 
The number of species occurring from here to the summit is very 
small, but this is amply compensated for by the number of indi- 
viduals found in what one may term the Gyrophora reticulata 
formation. The species collected were as follows: 
1. Staurothele umbrina (Ach.) Tuck.—Forming dark stains on 
rocks along the summit. 
2. Lecidea atrobrunnea (Ram.) Schaer.—Abundant on all kinds 
of rocks at 8000 ft. and above; exceedingly variable, and perhaps 
