Anomalous Endosperm Development in Maize anil the Problem of Bml Sports. 249 



not all the heterozygous factors could have been concerned in the segre- 

 gations. I have now to report the occurrence of a single half-and-half 

 purple-and-red seed which can also lie interpreted in either one of these 

 two ways. 



I do not recall having seen more than two wholly colored maize 

 seeds with one side red and the other side purple. The first one of 

 these was found on an ear of a race that was homozygous for red 

 aleurone hut which had been pollinated by a race with homozygous 

 purple aleurone. This seed may be interpreted equally well by any one 

 of the four hj^jotheses noted in this paper and is, therefore, of no 

 value in this discussion. 



The other red-and-purple seed (figure 6) occurred on an ear of 

 colorless maize that was pollinated from a plant heterozygous for aleu- 

 rone color. Since both of the parent plants were grown and the cross 

 made for purposes other than a study of aleurone color, nothing was 

 known of the aleurone factors concerned. Fortunately, however, the 

 factors are readily determined from an examination of the hand-pollinat- 

 ed ears of the parental and grand parental plants and of the cross- 

 pollinated ear on which the anomalous seed was found. 



A self-pollinated ear of the plant that furnished the pollen for the 

 cross had 15.5 purple, 71 red and 166 colorless seeds. If there had 

 been three times, instead of only about twice, as many purple seeds as 

 there were red ones, the common 27 — 9 — 28 ratio, produced only by a 

 plant heterozygous for the three factors C, R and P, would have been 

 clearly indicated. All of these factors must, as a matter of fact, have 

 been heterozygous. If P had not been heterozj-gous, no red aleurone 

 could have developed. If either one of the two factors C and R had 

 not been heterozygous, the 9 — 7 ratio of colored to colorless seeds, so 

 closely approximated by the records noted above, could not have been 

 realized. 



The pollen parent of the cross that gave the purple-and-red seed 

 must, therefore, have had the formula CcRrPp. The gametes of such 

 a plant are of eight kinds, made up of all combinations of the three 

 factors C, R and P. 



The ear of the colorless-seeded plant, pollinated with this mixture 

 of eight kinds of pollen, contained, in addition to the one purple-and- 

 red seed, 65 purple, 76 red and 41.3 colorless seeds. That is, there 

 were practically equal numbers of purple and red seeds and three times 

 as many colorless as colored seeds, or a ratio of 1 — 1 — 6. This result 



