3 i8 



MAR CHANT I A CE;. 



PAET II. 



can be admitted into the cavity below. This is a very 

 beautiful instance of the contractile vital energy acting 

 for the production of motion, its object being to supply 

 air, so essential to the health of all plants. White fila- 

 ments from the base at once fix the Marchantia to the 

 earth, and supply it with food. 



This is the youthful state of the Marchantia poly- 

 morpha, but after a time green points appear from 

 under little reddish scales on the surface, and these 

 are developed into stalks an inch or less in height, 

 which terminate differently, some in lobed shields, 

 others in spoked whorls, like a carriage wheel without 



Fig. 44. Marchantia polymorpha :~A, portion of frond seen from above, showing 

 lozenge-shaped divisions (a), with central stomata (6) ; B, vertical section, showing 

 the layers of tissue, and one of the stomata (g). 



the rim (fig. 43). The lobed shields are rather concave 

 and covered with little elevations, in each of which 

 there is a flask-shaped cavity with a long neck opening 

 on the "surface of the shield. In all of these hollows 

 there is a mass of cells full of an amorphous substance, 

 which is changed into spermatozoids, having the form 

 of delicate spiral filaments, thicker at one end, and fur- 

 nished with two cilia, with which they revolve in a spiral 

 within their cell. At last they emerge from it, and 

 come through the neck of the flask-shaped hollow to 

 the surface of the shield. 



In the companion female receptacles at an early age, 



