34 HUMPHREY 
At any rate, it is evident that under conditions prevailing in 
this part of California a second crop of antheridia appears before 
the close of a single growing season, and in the case of Fossom- 
bronza at least, when the supply of moisture is maintained, ferti- 
lization and ultimate development of the sporophyte proceed 
regularly, the spores ripening three or four months earlier than 
those of the winter crop. It is probable that the second growth 
of antheridia and archegonia begin to develop at least a month 
before the close of the rainy season, and this fact is of particu- 
lar importance to the plant as it insures the maturity of the 
sporophytic generation well within the rainy season. 
Certain of our liverworts show a tendency to develop tubers 
or other structures enabling them to resist drought. For ex- 
ample, in the southern part of the State, Geothallus tuberosus is 
a form bearing well-marked tubers, while in our own locality 
Frossombronza develops tuber-like thickenings of the stem, and 
well-defined tubers are to be found in the case of Anthoceros 
phymaiodes. All the plants employed in this study showed the 
presence of scales or hairs which in some instances secrete 
mucilage; these along with the mucilage cells within the thallus 
are structures undoubtedly serving as water-storage organs. 
According to Howe,’ aside from Anthoceros phymatodes, tuber- 
ous structures are not uncommon among plants of A. pearsonz, 
both species growing ordinarily in exposed places. In other 
parts of the world, hepatica bearing tubers have been found. 
For example Goebel’ describes two species of Authoceros, A. 
argentinus and A. dichotomus and a species of Hossombronza, 
F. tuberifera, common in certain parts of Chili. He regards 
the organ in the last named species a true tuber not unlike the 
same structure developed by our Axthoceros phymatodes, but 
considers the tubers of A. argentinus and A. dichotomus as trans- 
formed branches of the thallus, the ends of which, have become 
swollen and filled with reserve food products, very similar to 
what prevails in our common species A. pearsonz. Goebel * 
also reports certain species of /tzccza as developing tubers, 
MCoc. cit. p. 164. 
4120; \cit., (Pp. 293: 
2NOc. Cit... p. ZO. 
