PHYSIOLOGY AND MORPHOLOGY OF CALIFORNIA HEPATIC 29 
Of the above forms /vmbriarza, Targionia, and Porella are 
the most sensitively hygroscopic; at least when moistened they 
are the first to become turgid and resume activity. 
By dividing the total loss in weight due to artificial desicca- 
tion by the air-dry weight we obtain in percentages the actual 
fraction of the air-dry weight that is lost in drying. For exam- 
ple it was found that Fzmbrzarza, lost 6.06 per cent. of its air- 
dry weight while losses for the other five were: Zargztonza, 
i2.3\per cent.; Cry plomirim, 5.80 per cent. ; 7i2cc7a, o.47 
per cent. ; ossombronza, 8.23 per cent. ; Porella, 4.57 per cent. 
From these figures it will be seen that in the normal air dry 
state, 7Zargzonza contains the greatest amount of the water of 
constitution, while Fossombronza and Aticcza contain about two 
thirds as much. Fore/la, the only leafy liverwort used in the 
experiment, had given up all but a very small percentage of its 
air-dry weight followed closely by Crypftomztrium, one of the 
Marchantiacee. 
As a rule our summers are characterized by heavy morning 
fogs which drift in over the mountains from the ocean. These 
hang over the valley for three or four hours after sunrise greatly 
reducing the temperature and leaving behind, each morning of 
their occurrence, considerable precipitation, enough sometimes 
to result in dripping from eaves. The past summer (1906), how- 
ever, was unusually free from these fogs, even late in the season 
when ordinarily they are heaviest and most frequent. Fog- 
less mornings are characterized here by slight or even no pre- 
cipitation of dew and are forerunners of hot, extremely dry 
days. During such a season as the one just described it is 
probable that our liverworts remained in an absolutely dormant 
condition. It has many times been demonstrated that all our 
perennial forms on being moistened revive in from half an hour 
to twelve hours, resuming growth very promptly if the supply 
of moisture is constant. Campbell’ has shown in a recent paper 
that this peculiar adaptation is a property not only of certain of 
the hepaticz but belongs also to Gymnogramme triangularts, a 
fern common to this region, which dries up in summer, remain- 
ing dormant throughout the season, without the resulting death 
PVC. Cites Pp. O5- 
