38 HUMPHREY 



minate, thouirh sown at the same time as those in the case of 

 Riccia. A very few of the spores of either Fossombro7iia or 

 Cryptotmtriuni germinated. Though he did not duplicate in 

 every case the cultures of the writer, Professor Peirce had a 

 similar experience with all spores of the same (1906) crop. 

 This apparent loss of vitality is difficult to account for, unless 

 due to the unusual character of the weather during the spring 

 months. Ordinarily our last rains occur in April, by which time 

 the spores of the above-named hepaticae have either been dis- 

 charged or are maturing. An examination of the daily record 

 of precipitation from April i to the close of the season may be 

 instructive. Up to April i from January i the total rainfall 

 amounted to 10.04 inches. From April i to June 15 the record 

 was as follows: 



Amount of Amount of 



Date. Precipitation. Date. Precipitation. 



April 1 0.06 May 14 0.02 



" 10 o.oi " 25 0.34 



" 23 o.ii " 26 0.04 



" 24 0.03 " 27 0.51 



" 27 0.29 " 28 O.II 



" 29 trace " 28 o.ii 



May 10 0.01 June 3 0.02 



" II 0.02 " 5 0.73 



15 0.24 



" 26 trace 



From the above record it may readily be seen that from 

 April I to April 23 the total precipitation amounted to but .07 

 of an inch — scarcely more than a trace. Between the twenty- 

 third and twenty-seventh enough rain fell to revive the already 

 dried mosses and liverworts to a condition of perfectl}^ normal 

 turgidity and they remained so at least a week after the last rain- 

 fall. Now during April the spores of a number of our liver- 

 worts are only beginning to mature, and it is barely possible 

 that the prolonged dry period during that month interfered with 

 the proper ripening of the spores. On the other hand, spores 

 of certain forms, for example, Fossomhronia, which had fully 

 matured during March but were not gathered till after the 

 rainy season, failed to germinate ; and this suggests the possibility 

 of the vitality of the spores having been impaired by successive 



