One of my favourite flowers in the hanging baskets. Begonia flowers seem to come in big and small sizes. I think I heard that they have male and female flowers. But I might be wrong? They are quite fleshy and thick petaled, some of them are doubles like this one (double the normal number of petals). They look amazing BUT they are crammed with petals and that makes it harder, or even impossible, for bees and pollenating insects to collect nectar from their flowers. It also means that they are unlikely to be fertilised so I’m not sure if you can grow them from seed? This is all speculation on my part. I think I need to hear from a real gardener! I may not even have the correct identification of the plant!