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THE AMEBIC AN NATURALIST [Vol. XLIX 



i Carmine X White Marrow and 



l Carmine X Burpee Stringless a 



i Carmine X Refugee and recip 



Carmine X Keeney and recipr 



Carmine X Challenge Black ar 



Marrow X Burpee Stringless a 



3urpee Stringless X Refugee and reciprocal c X d 



Burpee Stringless X Keeney and reciprocal c X e 



3urpee Stringless X Challege Black and reciprocal cXf 



Refugee X Keeney and reciprocal d X e 



Refugee X Challenge Black and reciprocal dXf 



Keeney X Challenge Black and reciprocal e X f 



The Burpee crosses should be particularly watched to 

 determine if the assumed set of factors AIT is the cause 

 of the shoots and later spreading habit of the plant. 



The axis should be studied by means of accurate meas- 

 urement as far as possible. The judgment concerning 

 circumnutation would probably be necessarily more or 

 less indefinite. 



In crosses 4, 5, 8, 9, 11, etc. the type number should be 

 determined. 



The conclusions that can be drawn from observations 

 reported in the preceding pages are : 



1. That plant habit in beans is largely determined by 

 the presence or absence of three characters which have 

 been designated by the letters A, L, and T. 



1. A, the presence of axial inflorescence permitting an 

 indefinite growth, of the main stem and main branches, 

 and a terminal inflorescence causing definite growth. 



2. The length of the axis L, an important factor con- 

 trolling plant habit and probably governed by a series of 

 two or more factors for a length L,, L 2 , etc., which behave 

 after the fashion of Emerson's hypothesis for the inherit- 

 ance of quantitative characters. 



3. The climbing habit is due to a factor for circum- 



