840 



In the first case there arise only germ-cells of the constitutioh 

 ABC and abc. With self-pollination therefore segregation of 3 "red" 

 to 1 "green" must follow. In the second case there are four kinds 

 of pollen-grains and four kinds of ova, whereby F^ will segregate 

 in the proportion of 9 "red" to 7 "green". In the third case there 

 are eight different reproductive cells and segregation takes place in 

 the proportion of 27 "red" to 37 "green". 



Baur's hypothetical example of Cannas, which differ in 3 char- 

 acters, refers to one leaf-, one stem-, and one floral character, which 

 should show independent Mendelian behaviour. We now find that, 

 if we hold to the existing ideas, three leaf characters, which one 

 might perhaps be inclined to assume were in one chromosome, 

 behave, as though they might be distributed over two or three 

 chromosomes, which would be an argument for the dissolution and 

 mixing-up of the chromosomes in the synapsis-stage. 



The 17 green examples from (A' 4— 7) X (6^ 11 — 5) A'G have all 

 been planted out, most of them however died and only 6 grew 

 large enough to ascertain definitely that their leaf-edge completely 

 corresponded with the pure "green" descendants of 6^ 11. They may 

 therefore indeed be represented as aahbcc. With respect to the fruits 

 however they differ. Whilst those from G 11 and their offspring 

 possess at most a hardly noticeable red apex on some of the little 

 cones of the fruit wall, the ovaries of one of the "green" examples 

 of (i^4 — l)y:i{(r'\\ — 5)71*6 were clearly red, as was the case in 

 some of the examples, which had no red at all in the leaf-margin, 

 from (A*4 — l)y^{Gll — 5) Aj. A sister-specimen had, however, green 

 ovaries, so that for the factor red in the fruits the segregation indeed 

 occurs, independently therefore of the three leaf-edge factors, which 

 remain associated. 



The great variability of the red in the fruits, even in one and 

 the same plant, is the reason for my failure to determine with 

 certainty the number of factors for it. I can only say that at least 

 one of them can behave as if it wqyq independent of the three leaf- 

 edge factors. 



So far the segregation of "red" and "green" has been spoken of 

 as if all "green" individuals were alike. In reality however this is 

 not so. With sowings, not older than 1 to 2 months, no distinction 

 can be made other than that between red-edged and green, 

 because nothing more can then be seen. If however "green" 

 specimens are planted out, tlien a few months later it is found that 

 some oidy are wholly green, as G\l, but other specimens show a 

 narrow red edge on the upper half of the leaf, most distinctly at 



