Family Myrtaceae > Subfamily Myrtoideae > Tribe Myrteae.
There are around 95 species of shrubs and trees.
They have many branches often down to the ground and some sucker.
The bark peels off the trunk and larger branches.

The simple leaves are opposite to sub-opposite.
They have oil glands and the often prominent lateral veins join near the leaf edges.
Some have simple hairs on the small branches, leaves and flowers.

Axillary inflorescences are often a single flower but there can be a few.
Flowers have a hypanthium around the inferior ovary.
There are up to 5 sepal lobes on the hypanthium and 5 white petal lobes.

The numerous stamens curve over the ovary then straighten.
The dorsifixed anthers open via slits.
The ovary has up to 7 locules each with numerous ovules in up to 3 rows.
The single style has a small stigma.

The fruit are berries that are commonly globular but can be pear-shaped or ovoid.
They mature from green to red, purplish-red, cream, yellow or greenish-yellow.
The sepal lobes typically remain attached.
The flesh can be white, cream, shades of pink and red or have an orange tinge.
There are numerous seeds.

Three species are seen in Australia with P. guajava and its cultivars being the main ones.
Also seen are P. cattleianum the Cherry guava and P. guineense the Brazilian guava.