THE MODE OF INHERITANCE OF STATURE AND 

 OF TIME OF FLOWERING IN PEAS {PISUM 

 SATIVUM). 



By FREDERICK KEEBLE, 



Professor of Botany, University College, Reading ; 



AND Miss C. PELLEW, 

 Research Student, Botanical Laboratory, University College, Reading. 



The experiments recorded in the present paper, though incomplete, 

 throw some light on the nature of the Mendelian factors which deter- 

 mine stature in peas (Pisum sativum) and on the mode of inheritance 

 of earliness and lateness of flowering in this species. The experiments 

 were designed originally to investigate the latter problem — left un- 

 decided by Mendel's classical experiments on the inheritance of " time 

 of flowering," As our work proceeded, it became evident that this 

 function of the plant is not unconnected with certain, definite, morpho- 

 logical characters. Hence it becomes necessary to follow the course of 

 inheritance of these characters, e.g. length of intemode and thickness 

 of stem. In doing this, we have been led to conclusions concerning, 

 not only the relation of these morphological characters with flowering 

 period, but, also, the part which these characters play in determining 

 the stature of peas. We deal first with the latter point. 



Stature. Certain garden races of Pisum sativum grow tall and give 

 rise to tall-growing offspring ; other races are dwarf and breed true to 

 this character. Adopting Bateson's classification (1909, a) we call 

 "tall," those varieties which grow 5 — 6 or more feet high, "dwarf," 

 those which range from 9 inches to 3 feet. Between dwarf and tall are 

 various " half-dwarf" races which reach a height of about 4 feet The 

 actual height attained by the various races is determined in any given 



