282 



THE RRYOPHYTES 



the greater part of the chlo- 

 rophyll work (photosynthesis) 

 of the plant, and the chambers 

 are developed as protective 

 structures around them. Each 

 chamber is open above to the 

 air by a circular pore (Fig. 

 247, (7), which can be easily 

 seen in the center of each 

 diamond-shaped area. This 

 specialization of the upper sur- 



F.o. 248. The cups and buds of faCe f tlle *"* P^nt 



Marchantia to a light relation gives it a 



A, cup-bearing plant; B, section of a cup general resemblance to the 

 showing the buds arising from its bot- cell structure of leaves in seed 



torn ; C, a bud showing the two growing -. , 



points; D, young plant developing from plants and terns. 



thebud Some individuals of Mar- 



chantia (Fig. 248, A) will usually be found bearing cups (cupules) 

 which contain numerous green bodies. These are many-celled 

 reproductive organs, called 

 buds (gemmse), which de- 

 velop from the bottom of the 

 cup (Fig. 248, B). Each bud 

 has two notches at opposite 

 sides (Fig. 248, C), which 

 become two growing points 

 when the structure falls on 

 its side upon damp earth and 

 begins to grow (Fig. 248, D). 

 This is a characteristic and 

 very successful method of 

 rapid asexual multiplica- 



tion in Marchantia. 



The sexual organs of 

 Marchantia are developed 



FIG. 249. The male plant of Marchantia 



A, male plant bearing antheridial receptacles; 

 B, lengthwise section of a receptacle (semi- 

 diagrammatic), showing a row of sunken 

 antheridia upon the upper surface; the 

 youngest lie just back of the notches in the 

 receptacle, which are the growing points; 

 air chambers are also shown on the upper 

 surface 



