here is a piece of text I copied off another forum.
....This year he asked me to look in my, what he thinks are, hippy-
dippy organic, heirloom seed catalogs for black radish seeds. And I
found 2 different types: a Spanish black radish that was called mild.
Well, that's not the point here. Another catalog featured a German one
that was described as pungent....
If this is really the case - than I want that German stuff. I have
been eating the spanish black radish - thinking that it was the real
deal. You see I have a lot of information on medicinal and cleansing
values of black radish. The information is in Russian language- I
guess you can call it Eastern European, so they must be refering to
the type of black radish that they have there. Now I started to look
on google for that information - and it seems like the answer could be
found after a number of hours of work. - I just hope someone can help
me figure this out.

Also a few years ago I was searching google and found like 2000 seed
for $4.00 (black spanish). but I forgot to write down the website, and
that is another project. But if I could get my hands on the other type
- I am sure I would start multiplying it.

Here in Portland OR we have a health food store that sells black
radish $4.99/lb . But Grower's outlet has them for $1.69/lb - this
is in the spring\