HEPA TICAE. — MARCIIANTIEAE. 



i6i 



113) the apex that is to bear the antheridia divides repeatedly before they begin to be 

 formed, and the whole collection of apices thus formed produces antheridia ; the older 



I-IG. 112. /, // Fcgatctla co>nca. I LoiigitiKlinal section through the apex of a thallus ; /, the scales (lamellae| of thi 

 under side of tlie thallus, A' tlie air-chambers formed on the upper side and gradually roofed over during the formatior 

 of the epidermis E. II Surface-view of a portion of the thallus seen from above. ///, IV, V Marchantia polymorpha 

 development of the stomata on a receptacle in longitudinal section ; Sf the cells from which the barrel-shaped stomata an 

 formed, and which at first lie close to one anntlier ; the canal leading to the air-chamber is subsequently formed betweei 

 tliem. In V the cells containing chlorophyll are beginning to shoot out from the floor of the air-chamber. // aftei 

 Leitgeb, the other figures from nature. 



Fig. 113. Marchantia pcilymor/>ha. .-/ a horizontal branch ^ with two ascending male receptacles /i«. B \i. 

 longitudinal section through a male receptacle hn which is still developing and the part of the flat shoot from "'"^h it 

 springs ; bb scales, h rhizoids in a ventral channel of the receptacle ; o.> the openings of the cavities in which the 

 antheridia a are placed. C a nearly ripe antheridium ; st its stalk, -w the wall. D two spermatozoids niagn. 800 times. 



ones are in the centre of the disk, and groups of them succeed one another from the 

 centre to the circumference where the apices of the shoot are placed, each outer group 



