The four o'clock plant possess either white, green, or variegated leaves. Inheritance is uniparental: leaf color is determined only by the phenotype of the ovule source.

For example, if the seeds were derived from ovules of plants with green leaves, all progeny plants bore only green leaves, regardless of the phenotype of the source of pollen.

This inheritance is transmitted through chloroplasts in the cytoplasm of the female parent, since the pollen is tiny and contributes little cytoplasm to the zygote.