24 



HUMPHREY 



lying country about San Francisco Bay there is an interesting 

 hepatic flora consisting of types of most of the principal groups. 

 All of these forms fruit luxuriantly and are seldom found sterile 

 during any one growing season. 



Among the more common hepaticae of this region, and espe- 

 cially in the vicinity of Stanford University, are certain species 

 of Riccia^ including R. glauca and R. t7-tchoca7'pa, both of 

 which grow vigorously in localities of extreme exposure ; and 

 especially is this true of the latter, a liverwort structurally 

 adapted to such a habitat. Aside from several species of Riccia 

 two species of Fhyibriaria [Asterella), F. califor^iica and F. 

 violacea are met with, the former being quite common. In cer- 

 tain localities, especially along the high banks of arroyos, Cryf- 

 tomitriimi teneriim is found to be abundant. Along with it and 

 in places of severer exposure, occur formations consisting almost 

 exclusively of the highly resistant Targionia hypophylla. 



Along the banks of our coast-range streams, even where 

 these come down into the Santa Clara valley, occur such widel}' 

 distributed forms as Fegatella conica and Ma7-chantia foly- 

 mo7'pha. These however always grow in close proximity to 

 the water where throughout the year they may never be entirely 

 deprived of a supply of moisture. It is doubtful if these forms 

 would be capable of withstanding the effects of a dry season. 

 Three years ago the writer transferred several plants of Fega- 

 tella to a locality in the valley where conditions of light and 

 substratum were restored as nearly as could be done, at the same 

 time modifying and finally cutting off altogether the supply of 

 moisture. Bv lessening for a whole summer season the supply 

 of moisture it was found that growth of the thallus was greatly 

 checked and the resulting branches were much shorter. Plants 

 that were deprived of water dried up and died, all ability to 

 recover being lost as soon as the tissue had given up a certain 

 amount of the water of constitution. It cannot here be said to 

 what extent Marchantla polymorj^ha is capable of withstanding 

 drought, but since it is almost never found except where there 

 is a fairly constant supply of moisture it would probably endure 

 desiccation little better than Feg-atella conica. Other moisture- 

 lovinor liverworts found in moist shaded canons of the outer 



