Psidium cattleianum Lucidum

Psidium cattleianum & P. cattleianum Lucidum.

There appears to be a lot of confusion with the scientific names and forms of Psidium cattleianum.
Also, the same common names are shared across a number of plants.

The Australian Plant Name Index ‘APNI’ recognises the names:
    P. cattleianum,
    P. cattleianum var. cattleianum,
    P. cattleianum var. littorale and
    P. littorale.

Worldfloraonline (and an Australian government site) recognises
    P. cattleianum and P. cattleyanum, the Cherry or Red cherry guava and says its synonyms are:
    P. cattleianum var. littorale,
    P. littorale and
    P. littorale var. longipes.

CABI says P. cattleianum, the Strawberry guava has around 35 synonyms including:
    P. cattleianum var. cattleianum,
    P. littorale var. littorale and
    P. cattleianum var. lucidum.

The following is a summary of statements seen.

P. cattleianum var. cattleianum the Red cherry guava is a synonym of P. cattleianum.

P. littorale var. littorale is seen as a synonym of P. cattleianum as well as a distinct form.
P. cattleianum var. littorale the Strawberry guava is described as a larger tree than P. cattleianum
    with slightly larger leaves (to 10 cm long) on petioles around 14 mm long with slightly larger yellow
    fruit (about 4 cm across). (This fits the description of P. cattleianum Lucidum.)

P. cattleianum Lucidum is seen as a synonym of P. cattleianum and P. littorale and also as a form, variety
    or subspecies of P. cattleianum.
Its common names include Cherry or Lemon guava and both the Purple and Yellow strawberry guava.
It is said to differ from the var. littorale by slight differences in the form of the trees.

Psidium cattleianum is sold as P. lucidum the Lemon, Yellow or Yellow Strawberry guava.

P. cattleianum Lucidum (or var. or f. lucidum) the Lemon or Yellow guava has slightly larger yellow fruit (up to 5 cm)
    than P. cattleianum.

P. littorale var. longipes (a synonym of P. cattleianum) is described as both the
    Purple or cherry guava with cherry-sized purple-red fruit and
    Yellow guava with purple to deep purplish-red fruit with yellow flesh.

Ignoring the synonyms I will use:

    1. P. cattleianum as the Red or Strawberry guava with purple-red fruit.

    2. Psidium cattleianum Lucidum the Yellow, Lemon or Yellow Strawberry guava which is a larger plant with
    larger yellow fruit.

(A large Australian chain advertises them similarly
    P. cattleianum the Red Strawberry guava and
    P. cattleianum var. lucidum the Lemon or Yellow Strawberry guava.)

Psidium cattleianum Lucidum

The Lemon, Yellow or Yellow Strawberry guava is also seen as a form (.f) or variety (var.)
    of P. cattleianum or as P. cattleianum var. littorale.

It differs from P. cattleianum (detailed under that name) by the following.
They are not seen as shrubs but are larger trees with many branches.
The hairless leaves, up to 10 to 12 cm long are on longer petioles up to 1.5 cm.
The mature fruit are yellow and slightly larger being up to 5 cm across.

These seem to be the most common P. cattleianum trees in Brisbane.