A large tree in a park, most leaves are 7-10 cm wide. Silvery leaf underside. I did not see any samaras.
Hi D, I know A. rubrum well, but I don’t think this one fits. Plenty of similarities, but it looks different than the typical form. Unless it is a selected variety.. Additionally the bark on the entire tree is very dark, not what I am used to with rubrum.
@Nik, that's interesting N, Acer rubrum is variable and the bark does get darker as it ages. More thinking needed.
Also, typical rubrum has a great fall color, like the one pictured here. The fall color of the tree in question, on the other hand, is nice but nothing spectacular. Perhaps you are correct, D. It is probably just a variety with more trilobed leaves.
It looks a quite a lot like A. pycnanthum, which is 3 lobed, and more silvery underneath than rubrum. That's the Japanese cousin of the US red maple. The only thing is that 1) the outer lobes should be shorter than the central one, and 2) A. pycnanthum is rare enough that it's unlikely to be planted outside of an arboretum. Especially as the autumn color is nothing special. So, it's more likely some sort of A. rubrum, which as you've both noted, is extremely polymorphic. Also, the color varies by individual, some of them are quite unremarkable in autumn. Ah, I think I have it: A. rubrum var drummondii. 3 lobed leaves, very silver underneath. Fits yours.
Commercially prevalent Acer rubrum Red Sunset ('Franksred') for instance is described as being noticeably 3-lobed - the lobing alone of the tree in question should not be taken to indicate it is a particular kind of red maple. Likewise since red maple is characteristically glaucous beneath I wouldn't take the silveriness of this one to necessarily be of diagnostic significance.
