114 



THE THEORY OF THE GENE 



callus, young plants were obtained that were tetraploid 

 throughout. One of these gigas nightshade plants is 

 shown in Fig. 68, to the right, and a normal (diploid) or 

 parent type, to the left ; a flower of gigas is sho^vn above 

 to the right in Fig. 69 and the parent type to the left. A 

 seedling gigas is shown and a seedling of the parent type 

 above left, Fig. 69. 



Fig. 68. 

 Normal diploid parent plant of solauum to the left, and tetra- 

 ploid to the right. (After Winkler.) 



The differences in the cells of some of the tissues are 

 shown in Fig. 69. The palisade cells of the leaf of the 

 gigas type and the corresponding cells of the parent type 

 are shown below to the left ; the guard' cells of the gigas 

 stomata and those of the parent type are shown below 

 to the right ; the hairs of the gigas form and those of the 

 parent are shown at the bottom to the right ; the pith cells 

 of the giant are correspondingly larger than those of the 

 normal plant. The pollen grains of the giant are repre- 



