The Inheritance of Fruit Shapes in Capsella

"PUNNETT-Square". The abscissa displays the genotype of the haploid gametes of one, the ordinate those of the other parent: CD, Cd, cD, cc. They result in the combinations (first row of the square): CDCD, CDCd, CDcD, CDcc. The combinations of the second row would accordingly be CdCD, CdCd, CdcD, Cdcc, etc. The colours of the diagram represent the different phenotypes (G. H. SHULL, 1914).