Fragmentation of a qualitative character in Primula sinensis. The F1 (3) of a cross between the two parental varieties (1 and 2) is constant and somewhat intermediate in character, although white. The F2 progeny (bottom three rows) are highly variegated, atomizing the overall phenotypic difference between the two parents into a remarkable number of distinct traits. Phenomena like this bedeviled the efforts of many breeders, until Mendel, to find simple laws of inheritance. From  plate 7 between pages 298 and 299.
Howard Journal of Biology 2009 8:15 doi:10.1186/jbiol123