incomplete dominance. A heterozygous condition in which both alleles at a gene locus are partially expressed and which often produces an intermediate phenotype.
(google)
or
when the phenotype of the heterozygous phenotype is distinct from and often intermediate to the phenotypes of the homozygous phenotypes.
(my class book)
so, the snapdragon flower's color is homozygous for red or white
sorry it took a while :p