Hi, A bonsai friend needs to get rid of some of his trees for lack of space: we tend to buy, sow, or collect almost anything "just to try", but it can become too much. So he gave me an Acer triflorum, not so good for bonsai, but it will fit in nicely in my jungle of potted maples. And this one too, but he couldn't tell me what it was. It's not grafted, the leaves are rather small (5-6 cm), the new ones deep red, older ones dark green - the size of the leaves might not be really relevant since it has been in a small pot for at least two years I think and was cut back. Maybe Acer cappadocicum 'Rubrum'? The bark is greyish, with some very light green, almost yellow)...
Thanks Ken, I've searched the web and yes, it must be. Next step is to repot it without messing too much with the roots so it can fully develop.
I know lots of people sell it, but I don't believe in cappadocicum 'Rubrum'. In short, lots of cappadocicum pushes out dark red new leaves, and these seem to be sold as Rubrum. There is certainly no such cultivar being propagated. So, certainly cappadocicum of some sort, maybe if your lucky it will turn out to be subsp sinicum. These are very hard to distinguish from subsp cappadocicum when young, but the bark is a little more gray than pure yellow, the bases are more truncated and the new growth a little more crimson. New leaves stay quite dark for a long time. Samaras (deep red) give it away, as does, eventually, rough bark. Love all of the cappadocicums, though, and I actually think subsp cappadocicum has better fall color than the much smaller subsp sinicum.
Here's some new growth on subsp sinicum to compare with. Looks more crimson to me though of course different digital cameras will throw up different color profiles. Even still, guessing it is probably subsp cappadocicum.
You might well be right. The colour of the red leaves is darker on mine I think, but as you said it's difficult to capture the real colours depending on light, background, etc. The rain has stopped so here is a photo showing the top of the "trunk", and from this anle, the red of the leaves look lighter, pretty much like yours:
