Incomplete dominance is the phenomenon where none of the two contrasting alleles or factors is dominant. The expression of the character in a hybrid or $\mathrm{F}_1$ individual is intermediate or a fine mixture of the expression of the two factors. The inheritance of flower colour in Antirrhinum is a good example to understand incomplete dominance. There are two types of flower colour in pure state, red and white. When the two types of plants are crossed, the hybrid or plants of $F_1$ generation have pink flowers. The pink colour apparently appears due to mixing of red and white colours (incomplete dominance).