The foliage on this older variety of canna can be green, burgundy or striped. Mine was totally green (the burgundy/bronze leaves behind it are on an Ambassador) until this year.  It is now green except for 1 leaf which has a wide purple stripe. A variable wonder, this plant also produces flowers that can be any combination of bright red, white or yellow but all make you look twice to be sure you're seeing correctly!   It is quite a novelty.  It has been called the "schizophrenic canna".

Note the crazy, inconsistent combinations of flower colors

Note the one leaf with the wide purple stripe.