Xo. r>s.-)] 



INHEBITANCE OF HABIT 



559 



these. Some of them are mentioned in the following 

 paragraph. 



The character of the habit type is somewhat influenced 

 by the amount of branching the plants exhibit; open, 

 loose, bush beans are the result of few branches; the 

 close, dense habit of some forms is caused by profuse 

 branching. The size of a plant to some extent influences 

 the habit, although not as much in small ones like Chal- 

 lenge Black Wax. In Warren the size of the plant prob- 

 ably causes it to droop. In some varieties the number 

 and weight of the pods, as well as their position, cause 

 some plants to droop and assume a spreading habit when 

 old. Perhaps fineness and coarseness of branching 

 affect habit. 



One further matter that comes up for consideration is 

 the question of the effect of environment upon plant 

 habit. Its greatest effect, as would be supposed, seems 

 to be upon such quantitative characters as length of the 

 plant axis and probably the twining character to some 

 extent. Instances of adverse conditions resulting in the 

 almost total suppression of a character were noted in 

 plants grown on poor soil. They exhibited the slender 

 tips, typical of vines with axial inflorescence, but were 

 otherwise bush-like and erect. The accelerating effects 

 of very fertile soil on the growth of runner was also 

 noted. However, the environmental explanation for the 

 sudden appearance of runners among bush beans or of 

 pole beans among typical runners is open to question. 

 The most probable cause of such phenomena lies pri- 

 marily in the regrouping of the unit characters of habit, 

 combined at times with checking and accelerating factors 

 external to the plant. 



The investigations here reported offer a foundation 

 upon which more extensive studv on the subject might 

 be based. 



The following table suggests a few important cross 

 types and the varieties which might be used to ad- 

 vantage : 



