Arboretum staff don’t know when the fruit is ripe on their most important tree, sounds about right.
I went to fruit and spice last month and the senior staff member told us bilimbi and guava was all that was ripe , we proceeded to find 10+ species of great ripe fruits. Its like the staff move around their day to day with blinders on, or aren’t fruit people but work there. At least they knew which tree the Lucuma is I guess, even if it’s labeled.
Casimiroa Tetrameria ( wooly white sapote ) is tasty, some Casimiroa Edulis varieties are Hybrids with Tetrameria, such as “Suebelle”, one of the most common cultivars found in nursery’s in CA.
Did you see the big Jaboticaba?