The catalogue had a boxed feature called "Two Sensational Cannas". It referred to C. 'Mary Thilow' and C. 'Mrs. Pierre S du Pont'.
The boxed item stated that "These two varieties, owing to the fact that the roots are very difficult to store, will be supplied as growing plants only. These will be ready March 1st."
It has been our experience that the most difficult Cannas to store over the winter are the Aquatic Group. This is worse for the F1 aquatic hybrids like C. 'Ra', and C. 'Wye', but also applies to those F2 hybrids like C. 'Burbank', C. 'Austria', and C. 'Roma'.
I have only read about C. 'Mary Thilow', mentioned above, and it would be interesting to hear from anybody else who has any knowledge of that cultivar in recent times. The description in the Deer's catalogue stated that it has "Bronze foliage and brilliant rosy salmon flowers. 4ft (1.3m)."