22 HEPATIC^. 



Epidermis without pores, sometimes marked with dark gonidia 

 bearing cells. Inflorescence monoicous or dioicous, antical 

 (i.e. epigenous). Antheridia immersed in cavities scattered over 

 the frond, covered, solitary or few, rarely numerous. Involucre 

 shaped like a horn with an oblique scarious mouth. Perianth 

 and calyptra none. Oogonia solitary, naked, nestling in the 

 substance of the nerve. Fruit pedunculate, siliquoid, two-valved, 

 traversed by a columella or dissepiment. Elaters either mono- 

 spiral or containing only a Hexuose (not spiral) fibre. 



