Back when I grew Phantasy Sapphire,
Daylily (Hemerocallis 'Phantasy Sapphire') I never understood why the spelling of Phantasy was allowed. I don't know how many times I tried to write "Fantasy" on labels.
Google says Phantasy it is an alternate spelling, but back when I grew it, I had not heard of "phantasy". Maybe the hybridizer, Biaglow, had something else in mind when he gave it that spelling.