268 BOTANICAL GAZETTE [APRIL 
climatology of the’ Pacific Coast and of the Santa Cruz peninsula in 
particular, recognizing at the same time that the area under discus- 
sion is really an aggregate of a number of minor biological areas, each 
possessing distinct physiographic, faunal, and floral features, and 
marked by its own typical lichen species. 
Most people, ina general way, have the idea that California has a 
subtropical climate, and that name is often applied to it. In reality, 
owing to its great area and wonderfuly diversified topography, Cali- 
fornia has many climates, but the typical Californian climate is, 
more than that of any other part of the United States, a true cool 
temperate climate; and it is to the rather cool but remarkably equable 
temperature conditions that we primarily owe the interesting inter- 
mixture of lichens typical of unlike life-regions. 
As typical of the temperature of the Santa Cruz peninsula I quote 
the following averages for the twelve months of the year, as fixed by 
observations at San Francisco extending over more than half -a 
century: “January, 52.2°F.; February, 52°; March, 54°; April, 
55°; May, 57°; June, July, and August, each 59°; September, 60.8°; 
October, 60°; November, 56°; December, 52°.” 
These temperatures will favor the boreal or alpine forms such as 
Gyrophora polyphylla, Evernia vulpina, Lecidea caeruleo-nigricans, 
Rhizocarpon geographicum, and others of like character; while at the 
same time they will permit of the migration from warmer regions of 
various species of Ramalina, Dendrographa, Dirina, Lecanactis, 
Schismatomma, etc. 
While the temperature conditions of the whole Santa Cruz penin- 
sula are quite uniform, the annual rainfall shows great variation in 
different localities, ranging from 50 or 60 inches at Boulder Creek, 
and even more in the Big Basin, to 13 or 14 inches at Stanford Uni- 
versity. 
For detailed statistics on this whole matter, however, one must 
refer to Professor ALEXANDER McAptr’s valuable work upon The 
Climatology oj Calijornia. 
A study of the lichen flora of the Santa Cruz peninsula shows that 
it is more or less sharply divided into a number of biologic areas, 
which may be roughly classified as the maritime, foothill, chaparral, 
mountain-forest, and mountain-peak areas. 
