@FailForward That was a good call, I looked at the genus listing and found what it is!
*Echinocystis lobata*
*Echinocystis lobata*
@piggo There you go. I was thinking the same, but the locality does not match. The botanist I asked about your pics told me this is probably some non-European plant, but I gather you collected it in CZ (or around), right? So it's some import which went wild...
And indeed, [Wikipedia says](https://en.wikipedia.org/wiki/Echinocystis#Distribution) it's an invasive species in E/SE Europe:
> It has also been reported as an uncommon invasive species in the Örség Landscape Protection Area of Hungary near the Austrian-Slovenian border.
If the fruit matches, you've got it. 
@FailForward yep, the fruit is right. I saw it grown before, but that was maybe 5-10 years ago. Too bad the fruit is not edible. well, i might try it anyway 
ftr, the seeds were collected around 49.9958372N, 14.0224308E
ftr, the seeds were collected around 49.9958372N, 14.0224308E
@piggo @FailForward >ftr, the seeds were collected around 49.9958372N, 14.0224308E
I was thinking that you took them from one of these suspicious Chinese packages that were delivered unasked to random people.
I was thinking that you took them from one of these suspicious Chinese packages that were delivered unasked to random people.
@piggo Check photos of cucumber seedlings here: https://identify.plantnet.org/weurope/species/Cucumis%20sativus%20L./data (the little tree-like icon)