Psidium is a genus of approximately 70 species of trees and shrubs in the family Myrtaceae (order Myrtales), native to the warmer regions of the Western Hemisphere. Its natural range spans Mexico, Central and South America, the West Indies, and the Galápagos Islands.
Members of the genus are evergreen woody plants that produce simple opposite leaves and white to pale-yellow flowers with numerous stamens, characteristic of the myrtle family. The fruit is a berry with persistent calyx lobes at the apex, enclosing a fleshy pulp and numerous small seeds. Fossil pollen and leaf impressions attributed to Psidium or close relatives have been found in Paleogene deposits of Patagonia, indicating the genus has been present in the Southern Cone since at least the Eocene.
The genus is best known for the common guava (Psidium guajava), one of the most widely cultivated tropical fruits worldwide and grown extensively across the tropics and subtropics for its nutritious, fragrant fruit. Other species such as Psidium guineense (Brazilian guava) and Psidium cattleyanum (strawberry guava) are also cultivated or foraged for their edible fruit. The genus was formally described by Carl Linnaeus in 1753.
Etymology
The name Psidium derives from the Greek psidion (ψίδιον), a diminutive of pside or psoa, a term used in antiquity for the pomegranate — a reference to the superficial resemblance of the guava fruit to that of the pomegranate. Linnaeus applied the name when he formally described the genus in 1753.
Distribution
Psidium is endemic to the Western Hemisphere, with its natural range extending from Mexico and the Caribbean through Central and South America to the Galápagos Islands. The genus reaches its greatest species diversity in Brazil and the broader tropical lowlands of South America. Several species, most notably Psidium guajava, have become naturalized or invasive across tropical Africa, Asia, Oceania, and Pacific island groups following deliberate or accidental introduction.
Cultural Uses
The edible fruit of multiple Psidium species has been harvested and consumed throughout the Neotropics since pre-Columbian times. The common guava (Psidium guajava) is today among the most economically significant tropical fruits, processed into juice, paste, jam, and candied products across Latin America, the Caribbean, South Asia, and Africa. The leaves and bark are used in traditional medicine in several regions for their astringent properties. Strawberry guava (Psidium cattleyanum) is harvested both wild and cultivated for fresh consumption and preserves.
Taxonomy Notes
The genus was established by Linnaeus in his Species Plantarum (1753). Circumscription of the genus has varied considerably; molecular phylogenetic studies have led to the transfer of some formerly included species to segregate genera, and Plants of the World Online currently accepts approximately 70 species (as of 2026), while GBIF's backbone taxonomy recognizes a narrower set. Fossil material attributed to the Myrtaceae from Paleogene deposits in Patagonia indicates an early Cenozoic presence of the myrtle lineage in southern South America.
