BRYOPHYTES 291 



the body of the structure. The neck consi&ts of a single row of 

 eight cells surrounded bv a single layer of cells; when the egg 

 cell is mature, the axial row of cells becomes liquefied. The 

 antheridial branch (Fig. 140, h) bears a lobed, disk-shaperl body 

 with flask-shaped cavities which open on the upper surface. 

 The antheridia are borne singly in these ca^^ties and produce 

 great numbers of sperms which finally escape and swim in the 



Fig. 139. — Cross-section of M. polymorphs showing structure. 



thin film of moisture over the surface of the plants. Some of 

 these sperms reach the arch^onia, s^\im down the neck, and one 

 unites with the egg or oosphere (fertilization) . 



The cell which is formed by the union of the two sex cells 

 or gametes is the fertilized e^ and is the beginning of the next 

 or sporophyte generation. The young sporophyte develops into 

 foot, seta and capsule. The capsule bears spor^ and fiber-like, 

 spirally thickened cells known as elaters. When the spores are 

 mature, the elaters expand, bursting the capsule and scattering 

 tte spores. 



The basal part of the arehegonium persists as a cup-shaped 

 structure and Is known as the calyptra. The spores germinate 



