PHYSIOLOGY AND MORPHOLOGY OF CALIFORNIA HEPATIC^ 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 Aiieura, Fcgatella^ 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 fiisij-ormis 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, 3'et, unlike 

 Aneura, the spores of Anthoceros are known to endure at least 

 two years desiccation. Spores of Fimbriai'ia californica and 

 Targionia hypo-phylla 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 Targionia 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 followint; forms : Ricci'a o'huica^ 

 Fimbriaria violacea, F. californica^ Targionia hypofhylla^ 

 Fossombronia longiseta, Cryptomitrium tcneriun and Aneura 

 multifida 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 Fimbriaria failed to ger- 



