34 Russell — Comparison of the Structure of Hybrid 



mediately below the epidermis becomes differentiated also from 

 the ovarian tissue. The cells become enlarged and filled with a 

 peculiar content present in the epidermis also. This layer 

 shows rapid division and pushes up into the swelling. It is 

 impossible at this time to trace the gland initial cell. At this 

 time, the pollen mother cells are in the anaphase of the first 

 or heterotypic division. 



As the epidermal cells divide, the swellings become more 

 pronounced. Two subepidermal layers become involved. The 

 outer cells of the tubercles become enlarged and oblong while 

 the cells between the swellings become compressed and small. 

 The first gland initials are found at this stage. They are usually 

 situated at the base of the swellings and consist of one or two 

 cells with a large nucleus and richly granular protoplasm. At 

 this time the pollen grains are in the tetrad stage, and the mega- 

 spore mother cell is distinguishable. 



The swellings become deepened as the flower matures and 

 press together tightly so that they assume a squarish or oblong 

 shape (fig. 30). At this time the glands are fully developed. 



Fig. 30. Longitudinal section through mature ovarian wall, X 100. G = 

 gland in section; E = epidermis with waxy layer on outer surface. 



They have the same fundamental structure as the simpler 

 glands on the leaves, etc.; that is, they possess a set of 2 or 

 frequently 3-4 central cells running down into a mass of small 

 cells below. 



The gland is irregularly spherical in shape, and is composed 

 of many more cells than the glands on the pitchers. There 

 may be 60-80 cells concerned in the formation of the ovarian 



