290 



COLLEGE BOTANY 



gins and tlie upper surface is marked into rather definite ai'cas 

 which give it a superficial resemblance to an animal liver (Fig. 

 138) and therefore the common name "liverwort." In the 

 center of each area is a small opening into a chamber which 

 corresponds to the, area. The epidermal cellsi are transparent, 

 but arising from the floor of this chamber ai'e many delicate 

 chlorophyll-bearing cells. However, ohlorophvll is not restricted 

 to these cells, but is also foimd in other cells. On the lower 

 axial region are numerous hair-like structures known as rhizoids 

 and corresponding to- the root hairs of the higher plants. They 

 Fig. 137. fiq. i38. absorb Water and other raw 



food materials. The air 

 has free access to the cells 

 within the chambers and 

 affords the necessary stip- 

 ply of carbon dioxide. 

 The sunlight passes 

 through the upper epider- 

 mal cells (Fig. 13 9). 

 Therefore, it will be seen 

 that the plant has all tbe 

 factors necessary for pho- 

 tosynthesis. The anterior end of the plant is notched, and it is 

 from this point that the gTOwth occurs. 



The non-sexual reproduction is by means of small buds or 

 gemmce which are borne in tiny cups or cupules, along the axial 

 line of the upper surface. They are capable of growing into 

 new gametophvtes (Fig. 137). 



The sexual organs (Fig. l-tO) are borne in receptacles or 

 special branches arising from the upper surface of the thallus or 

 gametophyte body. The archegonial and antheridial branches 

 are borne on different gametophj-tes and therefore the plant is 

 dicEcious. The archegonial branch (Fig. 110, a) bears a star- 

 shaped body which gives rise to the archegonia. 



The archegoTiium is flask-shaped and the egg cell is borne in 



Fig. 137. — Marchantia polymorpha showing 

 two cupules bearing gemmule. 



Fig. 138. — Surface view of Marchantia poly- 

 morpha very much magnified. 



