112 MANUAL OF BOTANY 



mature the capsule dehisces, sometimes regularly by valves, 

 sometimes irregularly. 



A calyptra is formed during the growth of the embryo or 

 sporophyte, much as in Marchantia. When the capsule is 

 mature, a rapid growth of the short seta ruptures it at the apex, 

 and the sporogonium is exposed. It then dehisces as described. 



According to Goebel, there is a possible link between the 

 Hepaticse and the Chlorophyceae in the genus Aneura, from the 

 thallus of which certain cells are liberated which may be com- 

 pared with the zoospores of the latter. On liberation each 

 divides into two cells, and ultimately gives rise to a new gameto- 

 phyte. They differ from zoospores in not possessing cilia. 



