38 Russell— Comparison of the Structure of Hybrid 



In relation to the actual structure of the pitcher, longitudinal 

 sections of the rim have been compared. It has been noted 

 that, in the rolling, in the shape of the tip, in the amount of 

 thickening at the tip, the hybrid is intermediate in character. 



In all transverse and longitudinal sections of the pitcher, 

 the number of layers of false palisade, of subepidermal cells, 

 and the depth and character of the mesophyll, have all indi- 

 cated an intermediate relation in the hybrid. 



In the amount of thickening, either in sclerenchymatous 

 tissue about bundles, or in the number of striations on the 

 hairs of the inner lid surface, the hybrid is invariably inter- 

 mediate. 



Bisexual Hybridity 



Some apparent variations from the exact blending should be 

 noted here. On pages 16 and 17 there is an account of the 

 inability of the glandular surface of S. purpurea to blend with 

 the conducting surface of S. flava. The resulting mosaic effect 

 is described. This obtains also in the hybrid of S. purpurea 

 with S. Drummondii, and has been noted in the hybrid with 

 5. minor. The inability is probably due to the fact that S. 

 purpurea has evolved far in advance of all other forms, except 

 possibly 5. Sledgei. It would be interesting to know if of all 

 the forms this could perfectly blend with 5. purpurea when 

 crossed. Unfortunately such a hybrid has not been found. 



In the hybrid of 5. Sledgei with S. Drummondii, the develop- 

 ing glandular area is completely lacking; the impulse is too 

 weak for transmission. 



Other peculiarities of relation in parent and hybrid types 

 might be illustrated by the relation shown in comparisons of 

 counts obtained for glands. In every case practically the 

 hybrid shows fewer glands than either parent. It is almost 

 impossible to obtain a hundred or more counts from a given 

 surface, and compare it with a hundred similar counts from 

 exactly corresponding surfaces. The glands are grouped in 

 S. flava for instance around the rim, and down the median 

 back portion of the pitcher. They extend halfway down the 

 length. In S. Drummondii they are massed about the rim 

 too, but are very sparse just below. If the total number of 

 glands could be counted and compared, they would undoubt- 



