THE EMBRYO 



273 



divisions by walls which are oriented at right angles to one another. 

 Of the resulting eight cells, the lower four form the initials of the 

 root cortex and the upper four give rise to the root cap and the root 

 epidermis. 



At the same time further divisions take place in the embryo 

 proper, especially at two points in the lower tier which are destined 

 to form the cotyledons. At this stage the embryo appears more or 



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Fig. 145. Development of embryo in Capsella bursa-pastoris. 

 1914, 1919.) 



(After Soueges, 



