24 HUMPHREY 
lying country about San Francisco Bay there is an interesting 
hepatic flora consisting of types of most of the principal groups. 
All of these forms fruit luxuriantly and are seldom found sterile 
during any one growing season. 
Among the more common hepatice of this region, and espe- 
cially in the vicinity of Stanford University, are certain species 
of /eccza, including ft. glauca and Lt. trichocarpa, both of 
which grow vigorously in localities of extreme exposure; and 
especially is this true of the latter, a liverwort structurally 
adapted to such a habitat. Aside from several species of Atzccza 
two species of /zmbriaria (Asterella), F. californica and F. 
violacea are met with, the former being quite common. In cer- 
tain localities, especially along the high banks of arroyos, Cryf- 
tomitrium tenerum is found to be abundant. Along with it and 
in places of severer exposure, occur formations consisting almost 
exclusively of the highly resistant Zargzonza hypophylla. 
Along the banks of our coast-range streams, even where 
these come down into the Santa Clara valley, occur such widely 
distributed forms as Fegaiella conica and Marchantia poly- 
morpha. These however always grow in close proximity to 
the water where throughout the year they may never be entirely 
deprived of a supply of moisture. It is doubtful if these forms 
would be capable of withstanding the effects of a dry season. 
Three years ago the writer transferred several plants of /ega- 
tella to a locality in the valley where conditions of light and 
substratum were restored as nearly as could be done, at the same 
time modifying and finally cutting off altogether the supply of 
moisture. By lessening for a whole summer season the supply 
of moisture it was found that growth of the thallus was greatly 
checked and the resulting branches were much shorter. Plants 
that were deprived of water dried up and died, all ability to 
recover being lost as soon as the tissue had given up a certain 
amount of the water of constitution. It cannot here be said to 
what extent Marchantia polymorpha is capable of withstanding 
drought, but since it is almost never found except where there 
is a fairly constant supply of moisture it would probably endure 
desiccation little better than Fegatella contca. Other moisture- 
loving liverworts found in moist shaded cafions of the outer 
