That's fantastic. I've spent days pouring over images of wood grain trying to find a match and drawn an absolute blank.
Just a few mins on here and "Bingo" ! I've found another image of Poppy Oak wood grain and they match up perfectly. Thank You.
Could have been local (uk), or European sourced. The pips, as I understand it, are little branches that sprout, typically where the tree gets plenty of light, so parkland trees for instance. Where they are in a dense forest, the trees grow upwards for light so you get long straight (pip free) wood.
As mentioned previously the pips come from small side branches. Usually clusters of very small branches. Look at trees as you drive around and you'll see them.
I had some Oak trees milled in Surrey a few years ago and I've come across many pippy boards. In fact, I retained a lot of the 'waste' boards cut from the outside of the tree purely because they make nice feature pieces. I call it 'waste' because that's how it was described to me, but honestly I'm amazed such pieces are not retained as premium pieces.
Your photo seems to show a repeat pattern which suggests it may be a veneer. Well actually several veneers cut from the same board hence the repeat pattern.
Here's a section of one of my boards that I made into a table top recently.
Jon
[Edit.... Put the image back after I deleted it.... #-o ]