Just measured the leaf. It is about 7and1/2 inches by 14. I have not known it produce seed even when I had 3 or 4 plants at work. It does produce more than one leaf so is not monocarpic.
I once grew Streptocarpus cooperi which had an even bigger leaf. It only grew one leaf which died after flowering but produced lots of seed and seedlings would come up in the gravel under the bench so kept it going for a few years.
