THE MARCHANTIA GROUP 



281 



almost always larger and stronger than 

 the other. The lower surface bears nu- 

 merous filaments and fringes which are 

 formed in front of the growing points, 

 protecting them, and later 

 become distributed along 

 the lower surface. The 

 upper surface is marked 

 by diamond-shaped areas 

 (Fig. 247, A) which show 

 the position of curious 

 large air chambers (Fig. 



247 B\ that Contain very f r > female receptacle; c, cups producing buds. 

 J After Sullivant 



numerous filaments whose 



cells have well-developed chloroplasts. These filaments perform 



FIG. 246. A Marchantia form (Marchantia 

 disjuncta) 



FIG. 247. Structure of the thallus of Marchantia 



A, surface of thallus, the diamond-shaped areas marking air chambers ; B, a section 

 through the middle region of the thallus showing air chambers above, filled with 

 branching green filaments, and the fringes and root-like hairs (rhizoids) on the 

 lower surface ; C, surface view of the pore which opens into an air chamber 



