The four o'clock (<em>Mirabilis jalapa</em>) plant is a common ornamental species of <em>Mirabilis</em> (clade Angiosperms, flowering plants) whose leaf pigmentation is a well-known case of maternal inheritance. Moreover, chloroplasts are organelles that have their own genome which follows a maternal inheritance pattern in the majority of plant and animal species because they are contained in the cytoplasm (i.e., chloroplast DNA is inherited only from the mother because only the maternal cytoplasm persists after fertilization). Thus, chloroplast DNA has an inheritance pattern that challenges Mendel's Laws of inheritance (i.e., distinct from nuclear DNA). In the case of the four o'clock plant, the genes responsible for leaf color are located in the chloroplast genome and therefore these genes are transmitted from the female parent to the progeny. In this case, the leaf variegation is caused by two different types of chloroplasts that are inherited from the mother: normal green chloroplasts and defective chloroplasts (without chlorophyll pigment).
