Tiiu's post on tillage radishes mentioned the rat-tailed radish, and I've been meaning to blog back ever since. This is my first time growing rat-tailed radishes; we have a little patch of them in the demo garden. This type of radish (which could use a rebranding) is grown for the seed pod rather than the root.
They send up a flower stem much earlier than other radishes (though they all seemed to bolt soon this spring) and produce lovely pale butterfly-like flowers:
You can see the young green pods in the photo too. Here they are a week or so later:
Pods at this stage (about 3-4 inches long, no more than pencil width and not very lumpy) are delicious for snacking on raw. They taste very much like a radish (spicy!), with a hint of more vegetal, bean-like flavor. The green ones are hotter than the purple ones.
A week later, the pods (still both green and purple) were too tough for pleasant raw chewing and had lost flavor. I think they would cook well, though, and MG intern Linda Chappell located these recipes at the Kitchen Gardeners site. Read there about the history of the rat-tailed radish, and lots of other interesting information.
It's not too late to grow these this year. I intend to make a second planting in September.