30 HUMPHREY 
of the leaves as occurs in the majority of ferns. Not infre- 
quently one finds in the field quite fully developed prothallia of 
this species early in the autumn before the winter rains have 
actually set in. It is hardly possible for these to have devel- 
oped from spores that had germinated at any other time than in 
spring or early summer. In fact, it has been experimentally 
shown by Professor Peirce’ that the prothallia of this species 
may endure prolonged desiccation without evidence of the 
slightest injury, for on being moistened they very promptly re- 
vive and young sporophytes develop normally from these gameto- 
phytes of the preceding season. Perennial prothallia develop- 
ing tubers have been reported by Goebel? for the allied fern 
Anogramme cherophylla, common in southern Europe. Such 
structures belong to some of our liverworts but have not yet 
been shown to occur in the prothallia of any of our ferns. Aside 
from the common fern Gymnogramme, other pteridophytes native 
to California, ¢. 9., Selaginella biglovet and S. lepidophylla, 
the latter the well known ‘resurrection plant,” are reported by 
Campbell in the paper above referred to as remaining in a dry 
and dormant condition throughout the greater portion of the 
year, resuming active growth during the rainy season, at first 
absorbing considerable water through their leaves as do the 
leaves of Gymnogramme. 
To test the vitality of those liverworts that had been naturally 
and then artificially desiccated, a certain number of plants from 
each lot were placed on moist earth and others in Knop’s 
nutrient solution. In both cases the plants revived promptly 
and are now growing vigorously, producing fruiting organs in 
great number. A surprisingly small portion of the thallus of 
Targionta, Riccia, Fimbriarza and Porella was actually dead ; 
though in Fossombronia, Cryptomitrium and Anthoceros phy- 
matodes only the apical end including a small portion of the 
thallus appeared to be alive. Within five hours revived plants 
from each species were fixed with chromic one per cent. fixing 
solution and run up through the alcohols and bergamot oil to 
?Campbell, 1904: Resistance of Drought by Liverworts. Torreya, Vol. 4, 
No. 6, p. 85. 
3 Goebel, 1898: Organography of Plants. Part II, Vol. 1, p. 426. 
