242 A TEXTBOOK OF GENERAL BOTANY 
relationships are shown in Fig. 235, in which 7’ represents tall ; 
t, dwarf; Y, yellow; y, green; &, round; and 7, wrinkled. 
TO 

Fara ateaes 
TYR) TYR) TYR) TYR) TYR) TYR 
Maelo ne al 
Tyk|_ Ty) TyR| TyR| TyR| TyR| TyR| TyR 
pana Ta 
TY) TYr| TYr| TYr| TYr} TYr} TYr| TYr| TYr 
TEN eel ba 
Tyr Tye| Tyrl Tyr] Tyr| Tye Tyrl Tyr Tyr 



pau aioe papa 
tYR|_tYR} tYR) tYR} tYR) tYR| tYR tYR 
ea aad ae 
tyk| tyR| tyR) tyR) tyR) tyR) tyR| tyR 
CAAA IE EEA 
tYr| tYr| tYr/ tYr| t¥r| tYr| tYr| tYr 
one 
tyr) tyr| tyr| tyr| tyr| tyr| tyr} tyr 
Fig. 235. Diagram showing inheritance of three pairs of characters in 
garden peas: tallness, 7, dominant over dwarfness, t; yellow seed, Y, dom- 
inant over green seed, y; round seed, R, dominant over wrinkled seed, r 



Complementary factors. In all the cases that we have so far 
considered, a single factor is responsible for’the production of 
a character, but in some cases more than one factor is neces- 
sary. This may be illustrated by the case of two strains of 
