This one puzzles me over and over again... So, now when I have two plants of different origin (PI-631154 & GRIF 15020), they are different in interesting ways.

1. Flower spots: bright green in one, golden brown in another
2. Berries: extremely sweet in one, but hardly sweet at all on another (!)
3. One produces lots of berries (sadly, no seed in them yet), another hardly at all.

Both look quite similar as plants, though, and both easily survived the -15C or below temperatures I accidentally put them through...

Interesting, indeed...

For about one week. At lowest the temperature was -25C. The plants still live now, several years after the incident.