PROCEEDINQS 



OK THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. X, pp. 1-50. Plates I-II. January 18, 1908. 



STUDIES IN THE PHYSIOLOGY AND MORPHOL- 

 OGY OF SOME CALIFORNIA HEPATIC^. 



By Harry B. Humphrey, B.S. 

 Acting Instructor in Botany, Leland Stanford Junior University. 



The morphology and physiology of the Hepaticse have been 

 treated by many authors, but their work has been confined mainly 

 to the group as a whole. The intimate relations of the liver- 

 worts to their environments, have however, received only inci- 

 dental treatment. Ordinarily we are inclined to associate with 

 the Hepaticae an environment characterized by moisture and 

 shade. To a certain extent we are justified in doing so, for 

 the majority of the known species occur in just such a habitat, 

 many of the larger and more striking ones, such as 3Ionoclca, 

 Duviortiera and some species of Aneura^ being common in the 

 more humid regions of the tropics. On the o|:her hand many 

 species are known to occur normally in parts of the world where 

 climatic conditions are not so evenly balanced as in the tropics ; 

 many thrive in extreme northern and southern regions where 

 they are subject to great variations in temperature, while those 

 growing in regions like the west coast of the United States 

 must adapt themselves to prolonged periods of drought alter- 

 nating with six or seven months of rainy weather. 



It was with a view of ascertaining the nature and influence 

 of these various conditions common to certain California hepat- 

 icae that the present study was undertaken. 



Proc. Wash. Acad. Sci., January, 1908. i 



