Here is a photo of these very resilient little things.....

probably seeds of something else were already germinating underneath box? Are you sure the growth is from remaining roots?

It certainly seems so because these fine roots were discovered inside the box top soil too.

how close was the bird feeder .. and how many mice do you have storing seed under the tree box???

and i simply dont believe this happened overnight .. since there is etoliated white stems... they germinated at least days ago ...

ken

also flip to the images side: https://duckduckgo.com/?t=ffcm&q=etoliated&ia=web

It is hard to see clearly. Same seeds could be in the the pot too. Try picking up one or two of the sprouts and zoom in for a pic. Either way, keep it watered enough for the new sprous to not dry up and they will reveal themselves in due course. If they are Champaca baies I want some. :)

Certainly a mystery to me. NO bird feeder NO rats thanks to cats living in the yard. Don't those inside the potting soil look like roots just like the ones revealed under the pot, to you?

Any propoagation from roots would not have cotyledon (the first two leaves sprouting from a seed) which are qute visible in your first pic.

Yep. Those are clearly light starved sprouting seeds in the first picture, not roots. There are also some rhizomes of a creeping grass.

Thanks everyone! Glad I didn't break off any escaping roots, after all.