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PLANT MORPHOLOGY 



from the stalk and venter of the archegonium. This is soon ruptured and 

 carried upward on the top of the sporophyte as a conspicuous hood, which 

 may remain until the sporophyte is mature (Fig. 163C). 



The first division of the fertilized egg is transverse or oblique. Each 



B 



Fig. 165. Development of the archegonium of Milium affine, X400. A, young stage; B, 

 formation of primary axial cell; C, formation of cover cell and central cell, the former 

 divided by a radial wall; D, formation of primary neck canal cell and primary ventral cell; 

 E, archegonium with primary ventral cell and three neck canal cells; F, later stage with 

 seven neck canal cells; G, archegonium with egg, ventral canal cell, and eight neck canal 

 cells; H, later stage. 



segment becomes an apical cell through the activity of which a slender 

 elongated embryo is developed (Fig. 166). Apical growth continues for a 

 long time. Finally, at the upper end of the embryo, after the appearance 

 of two sets of four vertical walls, periclinal divisions cut off the amphithe- 

 cium from the endothecium. The amphithecium gives rise to several 



