Page:Mendel's principles of heredity; a defence.pdf/100

80 perceive a substantial agreement. Apart from the fact that from the union of a white and a purple-red colouring a whole series of colours results, from purple to pale violet and white, the circumstance is a striking one that among thirty-one flowering plants only one received the recessive character of the white colour, while in Pisum this occurs on the average in every fourth plant.

Even these enigmatical results, however, might probably be explained by the law governing Pisum if we might assume that the colour of the flowers and seeds of ''Ph. multiflorus'' is a combination of two or more entirely independent colours, which individually act like any other constant character in the plant. If the flower colour A were a combination of the individual characters A₁ + A₂ + … which produce the total impression of a purple colouration, then by fertilisation with the differentiating character, white colour, a, there would be produced the hybrid unions A₁a + A₂a + … and so would it be with the corresponding colouring of the seed-coats. According to the above assumption, each of these hybrid colour unions would be independent, and would consequently develop quite independently from the others. It is then easily seen that from the combination of the separate developmental series