DirtFarmer wrote:
Looks like a Petunia to me. A really dark red, but looks black. Haven't grown Petunias for 10 years or more and I have forgotten the names of the varieties.
The tomato has started to decompose, changing the pH of the fluid within and one of the seeds has germinated. I have seen that happen several times, usually on the compost pile.
Thank you for confirming the flower is a petunia. I appreciate your inside (no pun intended) chemical explanation; college chemistry is so far back in history, I've never used that bit of learning. Now I have to deal with the fact my "Forgetter" has gotten much better than my "Rememberer."