IV 



THE JUNGERMANNIACE^ 



103 



The early divisions in the embryo of Porella are less regular 

 than those in some others of the foliose Liverworts. The 

 embryo at first is composed of a row of cells, of which the 

 lowest, cut off by the first transverse wall, undergoes here 

 no further development. In Jiingermannia biciispidata ^ this 

 lower cell undergoes further divisions to form the filamentous 

 appendage at the base of the sporogonium. The next divisions 



Fig. 46. — Porella Bolafideri (Aust.)- Development of the archegonium, x6oo; C, cross-section of 

 young archegonium ; G, cross-section of the neck of an older one. The others are longitudinal 

 sections ; b, ventral canal cell ; o, the egg.  



in the upper part of the embryo correspond closely to those 

 described in Pellia and Aneura, but the succession of the walls 

 is more variable and the limits of the primary cells more 

 difficult to follow. The number of the cells, too, that contribute 

 to the formation of the capsule, cannot be determined exactly, 

 and there is evidently some variation in this respect, as there 

 is in the time of the separation of the capsule wall from the 



^ Leitgeb, Hofmeister, Kienitz-Gerloft". 



