PHYSIOLOGY AND MORPHOLOGY OF CALIFORNIA HEPATIC^ 27 



So long as the water of constitution is not disturbed the de- 

 gree of desiccation seems to make no perceptible change in the 

 reviving powers of all our common xerophytic forms. In the 

 preparation of a previous paper' quantitative experiments were 

 made upon Fossomhronia longiseta to ascertain the actual water 

 content of air-dried plants and to test the vitality of plants and 

 spores that had been for several weeks subjected to the action 

 of such a powerful drying reagent as glacial phosphoric acid. 

 The results obtained showed that the plants of this species in 

 the normal air-dry condition contain an appreciative amount of 

 water which may be removed without the slightest injury to the 

 vitality of the plant, while spores subjected to the same treat- 

 ment germinate quite as readily as those under perfectly normal 

 conditions. To extend these results the same experiment was 

 carried out with Targionia hypophylla, Fimbriaria californica^ 

 Riccia glauca, Porella bolanderi^ Cryptoniitrhitn tenerwn and 

 again with Fossomhronia longiseta. All material was collected 

 early in September before the first rains, was brought into the 

 laboratory where, with a fine stiff brush and other instruments, 

 it was carefully freed from any soil particles that might be 

 clinging to the rhizoids. Then to correct an error that might 

 creep in from the absorption of moisture by the plants from the 

 fingers or breath of the operator the plants were again subjected 

 to normal air-dry conditions a number of days. 



Following this the five lots of each plant, were carefully 

 weighed on a chemical balance and then placed at once in the 

 receiving chamber of a desiccator over a quantity of glacial 

 phosphoric acid. Here the material was left from September 

 21, 1906, until February 9, 1907, when it was again weighed 

 and the respective weight losses recorded. The weights before 

 and after artificial drying are given below : 



*Loc. cit. 



