BRYOPHYTES 



289 



The female reproductive organ is also more highly organized 

 than similar organs in the algae and is called an archegonium 

 (Fig. 159, c, c?). This archegonium is flask-shaped, with an elon- 

 gated neck and an enlarged venter. The outer cells of the 

 neck and venter form a protective wall layer like that of the an- 

 theridium, inclosing a central column of cells more immediately 



Neck 



Yen 



Neck-canal 

 cells 

 ---Wall cells 

 Ventral- 

 canal cell 



/-^^v* " ^ 

 a \ 

 Archegonial furrow Antheridial furrow 



Neck 



Archegoni 



Venter 



!-- $ Pronuclcus 

 IPronucleus 

 d 



Sperms 



Wall cells 



Sperm 

 mother 

 cells 



FIG. 159. Habit and sexual reproductive organs of Eicciocarpus 



a, habit of a single plant of Ricciocarpiis ; 6, section of the plant represented 

 in a cut through two reproductive furrows containing archegonia and antheridia; 

 c, section of young archegonium ; d, section of archegtraium with fertilized egg 

 cell containing male (d) and female (?) pronuclei; e, young antheridium; /, sperms 

 with flagella; g, section of mature antheridium 



concerned with fertilization and the growth of an embryo. This 

 central column of cells includes the neck-canal cells, the ventral- 

 canal cell, and the female gamete. 



Fertilization takes place when the plants are wet with rain, 

 dew, or spray, since this is the proper condition for liberating 

 the gametes and for the locomotion of the motile male gametes. 

 When the female gamete is ready for fertilization, the neck-canal 

 and ventral-canal cells disorganize and form a mucilaginous 

 substance which absorbs water, ruptures the archegonium at its 

 apex, and exudes in the form of a viscid drop in which the 



