194 ELEMENTS OF STBUCTUIIAL BOTANV. 



special cells in the archegonia, and resulting in the 

 production of spores. 



343. Liverworts. Kgs. 244 and 245 are representa- 

 tions of portions of a very common Liverwort, Marcliantia 

 ■polymorplia. It may be found growing along the borders 

 of marshes and in wet places generally, often with inter- 

 mingled moss. It is of a deep green colour, and usually 



spreads over a consid- 

 erable extent of sur- 

 face. There is no ap- 

 pearance of leaves, the 

 plant-body lying flat 

 upon the surface upon 

 which it grows, and 

 putting forth root-hairs 

 on the under siide. 

 Fig. 244. From the upper side 



arise peculiar stalked bodies of two sorts, as shown in 

 the figures ; the one consisting of flattened or slightly 

 convex disks, and the other being star-shaped. These 

 stalked bodies contain the reproductive organs. In 

 cavities on the uppei; surface of the flattened disks are 

 produced the antheridia, from the cells of which are 

 liberated the antherozoids. On the under surface of the 

 rays of the star-shaped bodies are produced clusters of 

 flask-shaped archegonia,- each with a germ-cell at its 

 base, and fertilization takes place in the manner already 

 described in the account of the Moss. As a result of 

 fertilization a capsule is developed which produces spores, 



Fig. 244. — Portion- of a Liverwort {Marchantia polymorplia), showing the 

 thallus and several stalked disks which bear the antheridia ; natural size. 

 (Thom4.) 



