26 HUMPHREY 
The Anthocerotacee are represented by Anthoceros fust- 
formis, A. pearsont and A. phymatodes the first two being 
very common, while the third, though not so widely distributed, 
is very abundant in certain localities near Stanford University. 
All three species are found growing luxuriantly in places of 
severe exposure, though thriving best in slightly shaded locali- 
ties. At one time it was supposed that A. fuszformis and A. 
pearsont were annuals but they were afterwards shown by 
Campbell’ to be perennial in habit. So far as the writer has 
observed Axthoceros phymatodes survives through the agency 
of its conspicuous tubers. In fact, it seems that virtually all of 
the thallus dies during the dry season except these structures 
which are packed with food-materials and serve as very effec- 
tive water-storage organs. ‘The other two species, while surviv- 
ing the dry season, resume development with but a compara- 
tively small amount of the old thallus persisting, though both 
species are highly mucilaginous and especially adapted to 
extreme conditions as described by Campbell.” Careful exami- 
nation of a large number of recently revived plants failed to 
demonstrate the presence of sex organs even in their early 
stages and it is probable that these develop after the new 
growth of thallus is well under way. With the exception of the 
two species of Spherocarpus it has been shown that all of our 
xerophytic forms are perennial, persisting from year to year 
unless artificially interfered with. Just how extended a period 
of desiccation they are capable of withstanding has never, so 
far as I know, been determined. In the autumn of 1903 the 
writer attempted to germinate spores of Hossombronza longiseta 
that had been collected in 1896. Some of the old plants along 
with the spores were placed in petri dishes containing distilled 
water, while others were sown upon moist earth. None of the 
spores germinated nor did the plants revive. The material was 
sent me from an eastern herbarium and I do not know the con- 
ditions affecting the material after collection. The failure of 
the plants to revive and of the spores to germinate can throw 
little light upon the question. 
1Campbell, 1904: Resistance of Drought by Liverworts. Torreya, Vol. 4, 
No. 6, p. 84. 
*Campbell, 1895: 1st ed., Mosses and Ferns, p. 117; 2d ed., 1905, p. 123. 
