Came across an interesting article published in the Vallarta Botanical Garden newsletter regarding Luc's Garcinia. Under the article on Page 9, there's a photo of a few gentlemen standing in front of one of the trees. Seems they thought it was G. intermedia at first but it's likely a separate species. Too many differences besides just the larger fruit size.
http://www.vbgardens.org/wp-content/uploads/2017/02/leaflet-feb-2017.pdf"We are constantly amazed at the complexity and diversity
of nature, especially here in the tropics. The more we
study, the more we realize what we don’t know! Take for
example Garcinia intermedia, a beautiful, edible, fruiting
tree that grows naturally in the Garden’s forest preserve
and is also represented by a specimen in the VBG’s Vallarta
Conservatory of Orchids and Native Plants.
This past month, a team of researchers representing
the Universidad Nacional Autónoma de México and Yale
University visited our Garden on a hunt for Garcinia
intermedia. They shared with us that the specimens
they encountered in the vicinity of Mismaloya Canyon
(between the VBG and downtown Puerto Vallarta) have
distinct morphological features, most noticeably larger
than normal fruit, that may indicate they are their own
separate species. The plants they encountered occurring
wildly in the VBG’s forest preserve have these same
characteristics. The researchers will need to go back to
their herbaria to further analyze their samples, both under
the microscope and the DNA sequencer, but their hope is
that the data will back up their hunch. We hope so too as
this would mean the description of a new “microendemic”
plant for our region—something totally unique to our
coast of Jalisco!"