There isn't one really, so far as I know, see link below, about the 'Welsh' oak

https://en.wikipedia.org/wiki/Quercus_petraea

The names you list are only well known and widespread common names anyway...

Thanks Bamboo. Yeah, I realise I was using common names. Just that it seemed unfair to the Welsh.
Mind you, I didn't know the Sessile Oak was also refered to as the Welsh Oak and also didn't know about Sessile Oak being the official national tree of Ireland.
Always a pleasure to learn something new.

I agree - both a pleasure and, I suspect, a necessity, to keep the brain working well...

Sorry the Welsh only get onions. Allium fistulosum, commonly called Welsh Onion.

We have Welsh poppies too OB! And the Tenby daffodil.
Hardly trees though!

Well even the name for the Welsh is not Welsh. It is Anglo-saxon and means 'foreigner'.

It's a pity the Welsh couldn't adopt the Dragon Tree (Dracaena).

The Welsh for Welsh isn't Welsh though... and tit for tat the Welsh for English, Saesneg or Saesnig, also means Saxon, related to the Scots Sassenach.
Good idea Stjohn.

learned quite a lot. Thanks for all the info. The Welsh came to Pawlet, Vermont to mine the slate for roofs etc. There still are huge water holes (beautiful) with slate galore. Absolutely no swimming ever!

Hm, well I never knew that, Wells... but was the slate for use over there or for shipping back to the UK/Wales?