Polygonum sp

I think it might be Carolina Jessamine, Gelsemium sempervirens. Here is a link that might be useful: Carolina Jessamine, Gelsemium sempervirens

"Hoovb's" Tiffany guess was inspired! There are a lot of similarities. But I've never had Tiffany in my garden. Also, I don't think this rose is a hybrid tea; it's more floribunda in type. And I think Tiffany has thorns, which this mystery guy does not. However, my mystery rose is still a "juvenile" and developing its adult characteristics. Thanks for the idea. Jallecta

Here's how I see it. There were volunteers that you believe to be from some red hybrids although you don't know for sure. I can't see reversion of any red hybrids reverting to what the others were that you mentioned. However, if he were growing any other varieties, perhaps some OP ones, then some of those volunteers could be the result of a cross pollination or indeed even aspecific variety. I'm not sure it looks like a typical gold/red bicolor, at least the ones that I've grown, which is quite a few. So I think the first thing you should do is to save some seeds and sow them again next year to see if all seeds give rise to the same plants and fruits that you've shown us or if it was ther result of a natural cross then it's the saved F2 seeds that you save, then be sure to put put enough plants from those F2 seeds so you can see any genetic segregation which should occur if the fruits you show are actually hybrid. Long paragraph, there, so if you have any questions, please just ask. Finally, no one can ID it for you as has been mentioned above and the reasons given for that were also given above and just now by me. That is, you have no starting point b'c you don't know exactly which varieties were planted by the landlord, so if you could ask, that might also help. Carolyn