WHITE: INHERITANCE OF HEIGHT IN PEAS 921 
апа Pellew Ото) as the factor for robust stems, but in the writer's 
interpretation of their results, it determines the difference in 
internode number. 
On the above interpretation, the factorial composition of the 
three classes of talls would be: 
(1) LeT = 20-40 long internodes. 
(2) LeT; = 40-60 long internodes. 
(3) LeiT» = 20-30 very long internodes. 
The factorial composition of the half-dwarfs would be: 
(4) Let = 10-20 long internodes. 
(5) leT = 20-40 short internodes. 
The true dwarfs on this scheme would represent the absences of 
Le and T or (6) let. 
Sufficient data have not yet been accumulated to determine 
in any detail the relations of these factors to each other except in 
the case of Le and T. Varieties with formula (1) crossed with 
(4) should and do give all long internode talls іп Е, and talls and 
half-dwarfs (long internode) in Е), Combination (1) X (5) gives 
long internode talls in Е, and approximately 3 talls (long inter- 
nodes) : т half-dwarf (short internodes) in F» Combination 
(1) X (6) gives all long internode talls іп Е, and an Е, population 
approximating 9 tall (1.1.) : з hd. (Li) : 3 hd. (s.i.) : 1 dwarf (s.i.). 
The two half-dwarf types, (4), (5) crossed with each other give 
all long internode talls in Fi, but an Е population similar to (1) X 
(6). Half-dwarf varieties (5) X dwarfs give intermediates in F, 
in some cases. The writer has no data оп this cross as yet. Half- 
dwarf varieties with the formula Let (4) crossed with dwarfs (6) 
give all long internode half-dwarfs іп F;, and approximately 3 half- 
dwarfs : 1 dwarf in Ез. 
Critics of Mendelian methods and conceptions will say again, 
as the above results are noted, “another unit-character has been 
split up." But the writer wishes to emphasize that with thé 
same genetic pea material that Mendel and others have used to 
obtain the Е, ratio of 3 talls : 1 dwarf, the same results will still 
be secured. The difference in interpretation has come from more 
detailed studies and the inheritance of height in peas has become 
complex only because of studies on new or distinctly different 
material, the characters of which, there is reason to believe, are 
due to distinct mutations. 
