As I've said before: common names can provide a useful veneer over the more turbulent sea of botanical nomenclature that lurks beneath!
It is curious that you should post about Pseudocydonia, as I've been noticing some quinces in the broad sense locally. I was unsure what they were, despite English-speaking locals calling them quinces.
I note:
"Cydonia oblonga has no serrations on the leaf margins and keeps its sepals in the fruit. Pseudocydonia sinensis has deeply serrated leaf margins and deciduous sepals"
p.197 in "Heirloom Gardening in the South: Yesterday's Plants for Today's Gardens"
by William C. Welch, Greg Grant, Cynthia W. Muelle
[https://books.google.co.uk/books?id=_6nQ681qy-4C&pg=PA197&lpg=PA197&dq=pseudocydonia+cydonia+difference]
Since my trees' leaves have smooth margins, that means my trees are Cydonia not Pseudocydonia.
Good to know.
But I was/am intrigued by the fruit being so 'scurfy', not smooth. I shall keep watching to see if the fuzzy fruit become smooth as they mature. Also, I guess fuzziness may vary with cultivar.
To keep this discussion on Pseudocydonia, I've posted my photos of Cydonia
here.
Mike