I am wondering the same thing. I'd love to collect the seeds from mine or nemesia and I don't (to be honest) even know where to look for where there might be seeds? I hope someone can help!
Kerstin

The seeds form in small green pods on the plant. You really have to watch for them. I had 4 or 5 plants last year and only one plant produced the seeds. This is my first year for planting my own seeds for this, so wish me luck.