"L'Arboretum des Barres" is said to be one of the "greatest Arboretums in Europe". It is certainly one of the most interseting in France and has a collection of maples. I went there last Saturday, but I didn't take all the photos I wanted, and because it was so sunny, the contrast between light and shade didn't help, not to mention gusts of wind when trying to take close-ups. But here are a few specimens :
All photos are more or less labelled, 21-05-08-lesb-22-aceropalus is actually Acer opalus ssp. obtusum.
