Genus Psidium is a plant classification that comprises several species of trees and shrubs commonly known as guavas. Alternative names for this genus include Psidium L., Guava, and Guayaba. Within the genus, there are numerous cultivars with distinct characteristics, and they range in size from small shrubs to large trees. Each species within the genus Psidium is usually identified by the shape and texture of its leaves, type of fruit, and seed characteristics. The most notable species include Psidium guajava, Psidium cattleianum, Psidium friedrichsthalianum, and Psidium grandifolium, among others. Synonyms for Genus Psidium include Myrtus guajava, Guajava L., and Feijoa O.Berg.