274 PRACTICAL BOTANY 



prothallus, from which the nutritive substances above 

 noted in the mature macrospore will have been 

 removed. 



A careful microscopic comparison of the spores sown as above 

 directed should be made from time to time during the process of 

 germination : it may then be ascertained that the contents of the 

 microspores divide into a number of cells, and ultimately rupture 

 and set free spermatozoids : also that the tissue of the prothallus 

 in the macrospore increases, rupturing the wall of the spore : 

 that archegonia are formed, from one of which the young seed- 

 ling originates. For further details the text-books must be 

 consulted. 



