Marvellous tree

I saw it somewhere on the web, but now can't remember the name... Those drooping leaves... Anyway, the photo was taken somehere in the Western US/Canada.
Would anyone help?
Thanks

 

Oxydendrum arboreum would be my suggestion, AKA "Sour wood"

 

I see that you have been looking at an Oxydendrum arboreum on the internet. Have you had any luck in finding a source for this tree?

Liz Spring

 

Please note that I live in Poland, so it's not likely we'd find a source suiting both of us.
But, I can recommend a fine link for anyone intrested in our sourwood (sorrel tree). Check it out.
http://www.floridata.com/ref/O/oxydendr.cfm

We have this little fellow growing here in Warsaw Botanical Garden, but it's well hidden and I haven't managed to locate it yet.

 

If its hidden away where it does not get full sun you will not see it in all off it's splendor as they like full sun to show
off.