Somehow, I managed to delete the thread while attempting to reply...
sorry
Anyway this was the picture you posted:
http://www.xs4all.nl/~cooper17/katrina/Misc/Roots.jpg
I'm wondering if you've planted them or can tell us more about the
plant itself? If it looks like this:
http://www.floridata.com/ref/h/images/heli_tu1.jpg
then it's a jerusalem artichoke; aka: sunchoke.
http://waynesword.palomar.edu/images/sunchk2b.gif
http://www.biologie.uni-hamburg.de/b-online/schaugarten/HelianthustuberosusL/Jer_choke.html
HTH,
sf
--
Practice safe eating. Always use condiments.