414 



BOTANICAL GAZETTE [may 



3. East and Hayes (loc. cit.) describe in certain of their families 

 grains which they call particolored. Their description leaves 

 little doubt that the writer is dealing with the same phenomenon. 

 These authors carried their work far enough to assign the P(R)c 

 formula to these grains. 



The tentative conclusion, therefore, may be reached that parti- 

 colored (faint) grains lack C but contain some partial substitute. 

 Just how this substitute is inherited is not clear as yet, but the 

 fact that it is heritable is undoubted. It is probable, although 

 not certain, that the same relationship between P and R as occurs 

 in the inheritance of the normal full color maintains itself also 

 under the particolored system. It must also be noted that this 

 unknown substitute for C is by no means always effective in bring- 

 ing any distinguishable color; its powers of expression seem to 

 be limited by conditions, a matter which will be discussed later. 



The question is now raised whether, in view of the possibility of 

 a complete series of color gradations, reliable counts of purple, 

 red, and colorless phenotypes can always be made. In answer 

 one may safely state that the phenotypes stand out sharply unless 

 particolored grains appear; the gap between light red and colorless 

 is a wide one. Particolored grains by no means appear in all cases; 

 the condition which brings them may or may not be present in the 

 germ plasm. When they do appear, they do so in considerable 

 numbers, so that a glance at the ear as a whole will determine 

 whether or not one has them to deal with. Thereby the investi- 

 gator is warned to focus sharply upon the boundary between light 

 colored and particolored, but even under the most practiced eye 

 some slight error is likely to creep in at this point. 



An anomalous case 



The possibility of at least partial substitution for the C factor 

 has been mentioned. We may be dealing with something of the 

 same sort in the following unusual case. East provided the writer 

 with an ear produced by PPRrccXpprrCC. The expectations 

 were obviously fulfilled, half of the grains being purple and the 

 other half colorless. The former, in the many crosses made, 

 regularly revealed the PpRrCc formula, which was expected; while 



