DEVELOPMENT OF PLANTS 



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its nucleus forms a globular mass of cells, the capsule, within-the 

 archegonium which keeps pace with its growth (Fig. 183, A, B). 

 The wall cells of this capsule are soon distinguishable, owing to 

 their watery contents and shape, from the other cells, which are 

 rather cubical and densely granular. The growth and division 

 of the granular cells continues until about 400 have been formed, 

 when they round ofif, become separated from one another and 

 increase greatly in size (Fig. 183, C). These large cells, called 



Fig. 183. Germination of the gametospore : A, basal portion of an arche- 

 gonium, showing the germinating gametospore in the four-cell stage. B, 

 later growth, forming a capsule with wall cells, w, which inclose large gran- 

 ular cells. C, a portion of the capsule, showing spore mother cells rounding 

 off and floating in the fluid of the capsule. D, the mother cells dividing 

 and forming four spores each. — H. O. Hanson. 



spore mother cells, form four spores each, as in the tetraspores 

 of the red algae (Fig. 183, D). The delicate walls of the cap- 

 sule break down as soon as the spores are matured, leaving them 



