LIVERWORTS: MARCHANTIA. 



153 



attachment at the base of tlie archegonium. Soon, as shown in fig. 185 at 

 the right, the outer portion of the sporogonium begins to differentiate into 

 the cells which form the eUiters and those which form spores. These lie in 

 radiating lines side by side, and form what is termed the archesforiuin. Each 

 fertile cell forms four spores just as in riccia. They are thus called the 

 mother cells of the spores, or spore mother cells. 



326. How marchantia multiplies. — New plants of marchantia are formed 

 by the germination of the spores, and growth of the same to the thallus. 

 The plants may also be multiplied by parts of the old ones breaking away 

 by the action of strong currents of water, and when they lodge in suitable 

 places grow into well-formed plants. As the thallus lives from year to year 

 and continues to grow and branch the older portions die off, and thus sepa- 

 rate plants may be formed from a former single one. 



327. Buds, or geminse, of maichantia. — But there is another way in which 

 marchantia multiplies itself. If we examine the upper surface of such a 



Fig. 186. 

 Marchantia plant with cupulas and gemms ; rhizoids below. 



plant as that shown in fig. 186, we shall see that there are minute cup- 

 shaped or saucer-shaped vessels, and within them minute green bodies. 

 If we examine a few of these minute bodies with the microscope we see that 

 they are flattened, biconvex, and at two opposite points on the margin there 

 is an indentation similar to that which appears at the growing end of 

 'he old marchantia thallus. These are the growing points of these little 

 buds. MTien they free themselves from the cups they come to lie on one 



