What is the stock plant in this grafted Acer?

iog

Good afternoon everyone. A friend in the U.S. has some beautiful new property. He sent me this photo of a nicely branching Japanese maple (he didn't mention which cultivar) 'grafted to something else in' his 'yard'. It seems like a slightly awkward pairing at the moment but perhaps as the Acer matures the stock and scion will achieve a more even flow? Out of curiousity, could anyone help me identify what was used as stock for this grafting? 

My thanks for any thoughts on this nice tree. 

Pete.8

I found this snippet from the RHS site

How to graft

Most plants need to be grafted within their own species i.e. Acer palmatum cultivars onto an Acer palmatum rootstock. However, it is sometimes possible to graft within a genus i.e. Acer japonicum, A. circinatum and A. shirasawanum can all be grafted onto Acer palmatum rootstock.

https://www.rhs.org.uk/advice/profile?pid=443

So it seems likely that the rootstock is an acer of some variety and most likely acer palmatum

iog

Thank you for this very helpful link Pete.8. I've sent it to my friend in the United States. I had suspected but did not want to suggest to him without a credible source that it was likely grafted onto the species of Acer. I know he'll enjoy looking at the RHS site. 

Silver surfer

iog said:

It seems like a slightly awkward pairing at the moment but perhaps as the Acer matures the stock and scion will achieve a more even flow? 

Very sadly an uneven match now will only get more obvious as time goes on.
See example below.This is Fraxinus.e

iog

Oh my.