ON HEPATIC^. 



287 



The peduncle is provided either with one or two grooves, 

 down which the radicles pass to the vein of the Frond. I 

 believe it will be found that two grooves alone exist in those 

 species in which the radicles are, during their course along 

 the vein of the frond, divided into two bundles. In Marchan- 

 tia, the portions closing in the grooves correspond to the in- 

 nermost scales overlapping the bundles of radicles in their 

 passage along the vein itself. M. Mirbel first I believe point- 

 ed out, that the surface of the peduncles which corresponds 

 to the upper surface of the frond, is in the cuticulate species, 

 similarly provided with stomata ; while the under surface of 

 the receptacle gives origin to similar radicles, which produce 

 by disruption similar scales. 



The outer involucra in the cuticulate species, are modifica- 

 tions of the inferior cutis ; in the ecuticulate they are pro- 

 ductions of the inferior stratum of parenchyma. In others 

 again of this last section, they are mere elongations of the 

 upper surface. 



The inner and partial involucra (perianthia) of some authors 

 are of later origin, and are extensions of the tissue immediate- 

 ly adjoining the base of each pistillum. 



The male organs or antherae vary a good deal in situation ; 

 generally they consist of a simple membranous sac, the mem- 

 membrane appearing rarely ? to become compound. 



In the foliaceous species they are axillary, in the frondose 

 they are contained either in cavities of the frond itself, or in 

 receptacles, which are indefinitely divided into cells, and 

 which are less frequently pedunculated than those bearing 

 the female organs. In these cells they are generally solitary, 

 they invariably communicate exteriorly by means of an open- 

 ing in the cell through the upper surface. Generally speak- 

 ing they are less developed than the similar organs of Musci, 

 although in some species of Anthoceros, they may be consider- 

 ed as attaining the maximum of evolution. Their contents 

 are similar to the fovilla of Pollen. It is impossible not to 

 be struck with the close similarity they present in appearance 



