1. Endosperm divisions have been examined further for determining types of aberrant mitoses in lines showing high rates of mosaic formation on the mature kernel. Evidence for a relation between aberrant chromosome divisions and observed genetic changes was obtained from control pollinations. The female parent was the same in both crosses. The resulting seed of one cross gives a high frequency of variegation, whereas from the other pollen parent there are very few or no mosaics observed. Cytological study of the endosperm divisions from both pollinations (10-12 days after pollination) showed a mean difference in percent of aberrant divisions of 3.24 (3431 divisions observed. P = .01-.05). This is a highly significant difference although many of the aberrant divisions are probably associated with changes that would not be observed genetically.

F. J. Clark