(a) The sea blush, Plectritis congesta, is a flowering plant that grows on the west coast of North America. Individual sea blush plants produce fruit that is either winged or wingless. Investigations have shown that this characteristic is controlled by a single gene with two alleles: • a dominant winged fruit allele • a recessive wingless fruit allele. Fig. 3.1 shows the difference in structure between winged fruit and wingless fruit phenotypes. [Figure 3.1]