Final answer:
The cultivar in the name Pisum sativum 'Early Perfection' refers to 'Early Perfection'. A cultivar is a plant selected for specific traits and is denoted by the unique name after the genus and species.
Step-by-step explanation:
The cultivar in the name Pisum sativum 'Early Perfection' refers to 'Early Perfection'. A cultivar, or cultivated variety, is a plant that has been selectively bred for certain characteristics, which are often represented by a unique name within single quotes following the genus and species name. The species name in this case is Pisum sativum, which is commonly known as the garden pea, and has been extensively studied by Gregor Mendel for its inheritance patterns. For instance, in Mendel's experiments with pea plants, round peas (R) were dominant to wrinkled peas (r).