If you are asking the valid name for the pictured canna it is C. 'Roma'. Like many canna cultivars the valid name has be changed by unknowing growers or catalogers over the past 100 years. The pictured cultivar was introduced around 1895 by C. Sprenger of Dammann & Co. in Europe. At that time, Mr. Sprenger was one of the first (along with L. Burbank-California) to successfully use the canna specie flaccida as a pollen parent to cross with the Crozy introductions of that time. The cultivar Florence Vaughan was a yellow bloom with red spotting (dots) and was confused with the cultivar Roma. Through out the mid to late 20th century Roma was marketed as Florence Vaughan. In the later part of the 20th century Roma has been sold as Yellow King Humbert (which is also not valid). We now have several synonyms that have replaced the valid cultivar name in the US for many cultivars.
If you are not confused yet, do a search for C. Italia. You will find it is a near match for Canna Roma. Both of which were introduced by Sprenger.

Regards,
Kent