70 THE PLANT OVUM LESS, vi 



section of an ovule shows it to contain a large cavity, the 

 embryo-sac or megaspore (see Fig. 126, D), at one end of 

 which is a microscopic cell (ov, and Fig. n B), consisting as 

 usual of protoplasm (plsm], nucleus (nu). and nucleolus 

 ('). This is the ovum or egg-cell of the plant : from it 

 the new plant, which springs from the germinating seed, 

 arises. Thus the higher plants, like the higher animals, 

 are, in their earliest stages of existence, microscopic and 

 unicellular. 



