Difference: HybridizerWilliamsonMary (r4 vs. r3)

After his death Mary Williamson carried on her father's (E.B.Williamson) work and nursery. Her interest in MTBs leads one to credit her with hybridizing in this group. But the actual hybridizer is hard to determine for any of these irises and we need further information to sort this out. After her fathers death in 1933 Mary continued to introduce irises he had hybridized and probably some of her own but Their work should be considered together. See E. B. Williamson.