By Joanmwoods
United Kingdom 
I have had - what I have believed to be a QUINCE in our front garden for years, it is a low growing shrub, thorny with beautiful red flowers in spring, followed by rock hard yellow small fruits in Autumn
I make lots of jams and even made jams for our daughters wedding favours BUT
I am frighten ed of this shrub as someone said there is a Chinese Quince similar which is very poisonous !?!?!
I went to our local Fruit & veg shop to buy a Quince and theirs are bigger, but seeds inside are same - lots of them compacted together!
I don't know what to believe :(
27 Apr, 2015
Answers
Agree with Owdboggy's answer - all three are edible, so don't worry about it - and tell that 'someone' they're talking twaddle...
27 Apr, 2015
The only difference between the fruit of Cydonia (proper Quince) and that of Chaenomeles japonica (which you have) is the arrangement of the seeds inside.
I had Quince jelly made from the fruit of the latter on my toast this morning. I am still alive (just).
The Chinese Quince is Pseudocydonia sinensis and the fruit of that is just as edible as the others.
27 Apr, 2015