PLANT Coors IN Maize 29 
biochemists, physiologists, and geneticists, it may be possible to reach 
conclusions in this field of quite as fundamental importance to biology 
as the recent results of similar efforts of cytologists and geneticists. 
GENETIC ANALYSIS OF COLOR TYPES 
In the preceding parts of this paper the several plant-color types of 
maize are described and the variations induced in them by diversities 
of environment are discussed. The remainder of the paper is devoted to 
a presentation of data of a moe distinctly genetic nature, and to an 
attempt at a factorial analysis of these data. 
The data are presented as if the F2 generation of the more complex 
crosses were the first which were obtained and on which hypotheses were 
formulated and appropriate tests made. As a matter of fact, this was 
not in all cases the actual procedure. In several instances the results of 
‘some of the simpler crosses were at hand and were used as an aid to the 
interpretation of the more complex ones when the latter were obtained. 
Moreover, the hypothesis presented here was not the only one, nor indeed 
the first one, formulated. As is usual in such work, various hypotheses 
were devised, tested, and discarded, until finally a factorial interpretation 
was found that fitted fairly well all the facts known. Many results with 
a bearing on plant color were obtained in other studies extending over 
a period of some eight or nine years. Since the practice of the writer 
is to number his pedigrees consecutively from year to year, an inspection 
of the pedigree numbers, as listed in the tables, suggests at once that some 
of the data presented as checks on other results could not have been 
obtained after these other results. Any data applicable as a test have 
been so used whether obtained for that purpose or in connection with other 
studies. Whether this mode of presentation is the best one must be 
left to the judgment of others. This at any rate is certain: the data could 
not have been presented chronologically and discussed in relation to such 
hypotheses as happened to be under test at the time any particular results 
were obtained, without adding unnecessarily to the complexity of the paper. 
CROSSES INVOLVING THE FACTOR PAIRS Aa, Bb, Pl pl 
Purple Ia « green VIc 
Generations F; and F2— When purple plants with purple anthers 
(type Ia) are crossed with plants lacking all red, purple, or brown 
