178 



Evans : Hepaticae of Puerto Rico 



phyllous branches. 



yfi 



with any other species of Leucolejeunea, in spite of the close re- 

 lationship of the two genera. 



The present paper concludes the discussion of the Lejeuneae 



Holostip 



to occur in Puerto Rico. Of the 



genera recognized by Schiffner the following four are apparently 

 unrepresented on the island : Ptychanthm, Thysananthus, Petiole- 



• * mm*. - _ 



mica. The last of these genera is abundant 



j 



Dicranolej 



to have a wider distribution in the West Indies. There is little 

 probability, however, that any of the others will be found there, 

 although each is represented in South America by one or more 

 species. Ptychanthus and Thy sanan thus, in fact, are essentially 

 paleotropic in their distribution and attain their highest develop- 

 ment in the East Indies and the neighboring parts of Asia. 



Yale University. 



