VOLUME LV NUMBER 3 
Se a Cee Oe ee TER ere gee eel ST 
ERE es eee Peng Oe : ; 
3 INHERITANCE OF FLOWER SIZE IN CROSSES BETWEEN 
SPECIES OF NICOTIANA’ 
E. M. East 
: THE 
: 
_ BOTANICAL GAZETTE 
‘ MARCH 1913 
(WITH PLATES VI-X) 
Since the independent investigations of Nmtsson-EHLE and of 
the writer demonstrated the feasibility of using the Mendelian 
notation to describe the inheritance of size characters that blend 
in the first hybrid generation, a number of botanical papers have 
appeared that supported this interpretation. These papers have 
considered the behavior in crosses of such characters as height of 
plant, size of leaf, number of leaves, time of flowering, and size of 
fruit. If the number of leaves in certain plants is excluded, this 
type of character is one particularly affected during development 
by external conditions. Since fluctuations produced in this manner 
are not transmitted, if the conclusions drawn from the sum total 
of our limited experimental cultures are to be given weight, the 
validity of the evidence in these investigations is not disturbed. 
At the same time, one must admit that these fluctuations obscure 
an analysis of the crude data. For example, plant B may be six 
inches higher than plant A when both are grown in the same envi- 
ronment, owing to a different heritage, but plant A may grow con- 
siderably higher than plant B if the environment of A is the best 
possible for maximum growth and the environment of B is poor. 
In this paper, therefore, I propose to consider the inheritance of 
* Contribution from the Laboratory of Genetics, Bussey Institution of Harvard 
“si y. 
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