cannas have roots not rhizomes

I bought some cannas late in the summer thinking that I could dig out the rhizomes during the late fall and save the rhizome to plant again next year. Today I took the plant out of the pot only to discover that there were no rhizomes, only roots attached to the stems. What kind of canna is this? I thought they all had rhizomes.
thanks

 

HI,
Any chance of a photo? Could be that you have a young seedling? :|

 

hmmmm, I will try, but now it is late at night. The plant is starting to die-off, but I will try to remember to take a photo in the next couple of days before it is completely gone. and thanks