i6 



Journal of Agricultural Research 



Vol. XIX, No. I 



The mean number of nodes without branches in the Fj hybrid plants 

 was 1.05. The distribution (fig. 6) was far from normal, and there is 

 some indication of two modes. Seventy-nine of the individuals were at 

 zero. Of the remaining 41 plants the largest number, 12, had 3 nodes 

 without branches, with a fairly uniform distribution ranging from i to 9. 



The significant correlations outside the group 

 were coherences with both of the characters in 

 the male branch group, number of suckers and 

 length of internode on third. The disherences 

 are with secondary branches and days to pollen. 



SO 



^O 



\ 



\ 



/o 



Iddx 



NODES above; group 



NODES ABOVE 



In teosinte of all varieties there is almost with- 

 fj out exception one node above the uppermost 



^^^H 1 branch. In maize the number varies from 8 or 9 



to 2 or 3; only in rare and abnormal specimens 

 is it reduced to one. The limits as observed in 

 the Tom Thumb variety are 3 and 5, with the 

 mean at 3.4. This character, while not so con- 

 stant as total leaves, is less subject to environ- 

 mental influences than most of the characters 

 recorded. 



There is some question of the propriety of con- 

 sidering the number of nodes above the ear in 

 maize as strictly homologous with the number 

 of nodes above the uppermost branch of teosinte. 

 In maize the uppermost branch, or ear, is nor- 

 mally the best developed, while in teosinte the 

 most fruitful branch is usually the third or fourth 

 from the top. See Tables I and II. 



If the uppermost branch in teosinte is not 

 homologous with the uppermost branch or ear in 

 maize, the complete absence of any trace of a bud 

 in the axils of the leaves above the upper ear in maize calls for some 

 explanation. It is difficult to believe that branches in the axils of the 

 upper leaves of maize could have be^n so completely suppressed as to 

 leave neither a trace nor a tendency to reappear as an abnormality. It 

 appears more reasonable to assume that in maize additional nodes have 

 been intercalated or that these sterile nodes in maize, instead of i;epre- 

 senting a change from the condition found in teosinte, have been derived 

 from a distinct ancestor. 



In the first generation there were two plants with one node above and 

 three with two. The range in the second generation was from one to 

 four, with one possibly abnormal plant with none. The distribution 



Fig. 6. — Nodes without 

 branches : frequency dis- 

 tribution of plants in Fj. 

 Class value, one node. 



