168 



PRACTICAL BOTANY. 



FIG. 96. A mass of Marchantia poly- 

 morpha bearing the male inflores- 

 cence. (After Bennett and Murray.) 



morplia, is one of the largest of the class and is well suited 

 for study. 



There are two modes of asexual reproduction. By one, 

 buds or gemmae are formed in little cups or cupules which 



grow on the upper surface 

 of the frond ; these, when 

 ripe, fall out and are scat- 

 tered over the ground, 

 where they take root and 

 produce new plants. By 

 the other mode new and 

 separate plants result from 

 the dying away of the old- 

 est portions of the frond. 

 The frond branches dicho- 

 tomously ; as the older 

 part dies, the branches 

 become separated, and each continues its existence as a 

 new plant. Reproduc- 

 tion by this mode is said 

 to be by innovation. 



There is considerable 

 variation in the different 

 orders of Liverworts in 

 the positions of the or- 

 gans of reproduction. In 

 some orders both the 

 male and female inflores- 

 cences are borne on the 

 same plant ; that is, the 

 Liverwort is monoecious. 

 In other orders the plant 

 is dioecious. In the com- 

 mon Liverwort the male inflorescence is borne on umbrella- 

 shaped branches. The branches rise an inch or more from 



FIG. 97. An antheridium of Marchantia 

 polymorpha. The antheridia are borne 

 on the upper surface of the umbrella- 

 shaped branches seen in Fig. 96. B 

 are antherozoids that have been set 

 free. (After Goebel.) 



