Yes, this is a flowering radish in my bicycle basket.
I was using my radish crop as a trap for flea beetles, so i wasn't expecting a surplus of large radishes. I let them go to flower in hopes of collecting seeds. As an inexperienced radish-grower, i began to look for the seeds in the flowers, with no luck. Nothing that even resembled seeds. Thankfully, a quick search on the internet proved successful.
How to harvest radish seeds: Wait till the radish begins to flower. Radishes are really amazing, because their stocks grow really thick and high, with numerous leaves. I like them because they look so different from how you would buy them in a grocery store. That is one of my favourite things about gardening - seeing and understanding how things grow. Shortly after the radishes begin flowering, they will start producing these pods from the stalks. They look like pea or bean pods. Depending on how long you leave them for, you can get quite a few! After awhile, I pulled the radish, and hung it to dry on a neighbouring tree. Some people hang them to dry in their garages. You should wait for awhile - probably a week depending on the weather - it has been really hot and humid here so the pod are taking longer to grow. I even cut the pods off of the stocks onto a baking tray, just as an experiment. After the pods are dry and brittle, you split them open and pick through the flesh to find the tiny little seed. I am waitng a little bit longer for mine to dry out a bit more, then i will package them in little paper envelopes, give some to my friends, and wait for next season to plant!