I assume you are aware that this is a very poisonous plant and should never be handled with bare hands? The alkaloid poison that coats all parts of the plant including the seeds can be absorbed through the skin. Take care.

That said, the seeds are contained within the blooms but are very, very small. You can winnow out much of the seed head duff by placing the heads in a sack and threshing it. You can plant the small seeds with what little duff remains. They require 4 weeks of cold stratification to germinate.

Dave