104 AMERICAN FERN JOURNAL 
mentioned, and in more exposed positions its fronds are 
killed in unusually cold winters; otherwise it retains 
continuous verdancy and maintains continual growth. 
The — pinnae reflect the moist conditions under which 
it grow: 
Our aa class of ferns are those which grow during 
the summer, and in winter lose their fronds and retain 
- yitality only in their roots. The most abundant of 
these ferns are Adiantum pedatum, Cystopleris fragilis 
and Athyrium filix-foemina. It will be noticed that 
these are species which are common over a large part of 
the country, and with us they occur in that_part of our 
territory which differs little in physical character from 
their habitats elsewhere. The precise stations which 
they inhabit here are probably more restricted than 
in regions where the rainful is more abundanf and better 
distributed. Here, their requirement of abundant and 
unfailing moisture at their roots, confines’ them very 
closely to the margins of streams and springs, and to 
bogs. 
I have, in this imperfect outline, endeavoured to 
place before you a general idea of the southern California 
fern-flora, and to indicate the effects of external factors 
in determining the distribution, the habits of life, and 
the structural forms of the various members which 
constitute it. The ferns are not an exceptional family 
of plants, nor is California an exceptional region, in 
respect to the conditions which determine plant life. 
These laws are universal in their application to all 
vegetation, and to all parts of the world. The study of 
the results of their decisions upon the life of the plant- 
kingdom where they rule the court of last resort, is a 
study fruitful and interesting, and there is no place 
where it cannot be prosecuted. 
San BERNARDINO, Ca., 
