318 Alexander W . Evans, 



certain species than in others. Sometimes the trigones are so 

 poorly developed that it is difficult to demonstrate them. 



The underleaves are undivided and vary in outline from oblong 

 to orbicular or even reniform. They are attached by an arched 

 line, the base is cuneate and often decurrent, and the margin is 

 quite entire and either plane or more or less revolute. The rhizoids 

 when present arise from a very rudimentary disc. 



According to Sj^ruce the inflorescence in Dicranolejeunea is 

 typically paroicous, although he admits that a dioicous infloresc- 

 ence sometimes occurs. Stephani describes paroicous, autoicous, 

 and dioicous species. In all the last, however, he admits that the 

 male inflorescence is unknown. The great difficulty in demon- 

 strating the vestiges of antheridia in paroicous species after the 

 sperms have been discharged makes it possible that some, if not all, 

 of the species described as dioicous may in reality be paroicous. 

 It should also be remembered that certain monoicous species occa- 

 sionally produce individuals in which antheridia but no archegonia 

 are present. 



The female inflorescence is sometimes borne on a leading branch 

 and sometimes on a more or less abbreviated branch. In almost 

 every case two subfloral innovations are developed below a primar\' 

 inflorescence, although occasionally only one is present (Figs. 7, 8). 

 The innovations are usually short and are often terminated by secon- 

 dary inflorescences. These in turn may develop new innovations 

 upon which tertiary inflorescences may arise, but no cases have been 

 observed in which inflorescences of a higher order have occurred. 

 The innovations are typically in pairs, even in connection with secon- 

 dary or tertiary inflorescences, but single innovations are more fre- 

 quent in such cases than in connection with a primary inflorescence. 



The perichaetial bracts (Figs. 7, F— K; 8, 1— K) are usually distinctly 

 smaller or at least narrower than the leaves. The lobes show a stronger 

 tendency to be toothed, and dentate bracts occur in certain species 

 where the vegetative leaves are entire. The lobules are rarely well 

 developed. In most cases they are exceedingly minute and may even 

 be reduced to a hyaline papilla. The bracteoles are usually larger 

 and broader than ordinary underleaves, but they show less tendency 

 to be toothed than do the lobules of the bracts. 



The perianth (Figs. 1 , 8) yields several of the more important 

 characters of the genus. It is distinctly compressed and the sharp 

 lateral keels bear dentate or spinose wings variable in width. The 

 antical surface is sometimes plane, sometimes slightly concave, 

 and sometimes bears a very low keel without either wing or teeth. 



