PHYSIOLOGY AND MORPHOLOGY OF CALIFORNIA HEPATICZ 37 
the xerophilous conditions under which the plant grows. The 
spores are positively known to maintain their vitality for at least 
two years but for how much longer, cannot be said. The thin- 
walled spores of such forms as Aneura, Fegatella, Radula and 
Porella withstand but little drying, losing all germinating power 
within a few months at most, which fact would seem to be evi- 
dence in favor of the statement that the thick exosporium is a 
protective structure. 
Spores of Anthoceros fustformis one year and eight months 
old, when sown on sterilized soil germinated copiously within 
two weeks. Here we have an instance of spores that are known 
not to require a resting period before germinating, yet, unlike 
Aneura, the spores of Anthoceros are known to endure at least 
two years desiccation. Spores of /zmbriarza californica and 
Targionia hypophylla two years of age were sown on sterilized 
earth and kept well watered. These germinated within twelve 
and fifty-six days respectively. This wide discrepancy is diffi- 
cult to account for. The soil was kept as free from fungi as 
possible: however, only a few of the Zargzonza spores ger- 
minated and this fact may have been due to reduced vitality from 
prolonged drying. Further experiments with spores of this 
genus are necessary ; in fact, germination experiments conducted 
out of doors are the ones of greatest value. Such a series of 
culture experiments was started more than a year ago in the 
Stanford Arboretum but before results of any value were ob- 
tained the cultures were accidentally destroyed by a workman. 
It was then too late in the season to start another series, it being 
very near the close of the rainy season. A fresh collection of 
spores was made from the 1906 crop and several artificial cul- 
tures were started indoors, using both sterilized and non-steril- 
ized earth and Knop’s nutrient solution. The spores used in 
the various cultures were of the following forms: /tzccza glauca, 
Fimbriaria violacea, F. californica, Targionia hypophylla, 
Fossombronia longiseta, Cryptomitrium tenerum and Aneura 
multiida major. 
No spores of the first mentioned plant have yet germinated, 
though sown six months ago after a resting period of five 
months. Spores of both species of Azmbrzarza failed to ger- 
