76 HANDBOOK OF BRITISH HEPATIC^. 



leaves being divided to within one-third of the 

 base, with the margins quite entire. It is a smaller 

 species and more of an olive green. 



Sub-tribe IV. TRIGONANTHE&, Spruce. 



Fertile female branches in many, not in all, 

 on the back side. Leaves alternate, rarely 

 opposite, from the often broad, truncate apex 

 more or less deeply two to four (rarely six) 

 dentate, lobate ; margin for the most part 

 entire, plane or incurved (never recurved) ; 

 flowers constant on posterior branches ; 

 elaters dispiral. 



This sub-tribe is, with very rare exceptions, well 

 distinguished from the two preceding ones by the 

 female flowers being hypogenous, or postical, 

 usually on a branch shortened down to the floral 

 envelopes alone. Not only are the female branches 

 mostly postical, but normally leafy branches, having 

 the same origin, exist in nearly every genus ; and in 

 some genera all the branches leafy, floriferous and 

 radicelliferous are solely postical. The trigonous 

 perianth (with the third angle on the under side), 

 usually so constricted upwards as to end in a 

 narrow pyramid, prevails nearly throughout the 

 Trigonanthea. 



The equably tristichous foliage, which with few 

 exceptions prevails throughout the Ptilidiea, has no 

 parallel in Trigonanthece, and rarely any approach 

 to it, Spruce. 



