He pa t icce of No i -fh A nw t 'ica . 5 



we have iu common with Eiighiud and the lower latitudes of 

 Continental Europe. 



III. Austral: including the forms found in the southern 

 border states from Texas or New Mexico to Florida, some forms 

 being common to Mexico or the West Indies, or both, and a 

 few found in Europe. 



IV. Occidental: including the Pacific border region from 

 Lower California to British Columbia, and possibly to Alaska, 

 including also the species of the Sierra Nevadas. 



Y. Cosmopolitan: including species more or less common 

 to all portions of our territory, all of which are also common 

 to Europe. 



The above divisions are, of course, merely tentative, and 

 may be considerably modified by a further knowledge of the 

 distribution of individual species. (See Appendix A.) 



Our species may be summed up as follows: 



ESSENTIAL CHARACTERS 



From this brief outline or introduction to the more gen- 

 eral characters of the hepatics, we must now consider the 

 special or characteristic habits of the group and its subdivi- 

 sions. As the plants of this group all manifest two distinct 

 phases in their cycle of growth or life history, it will become 



