Definitely not P. × pruhoniciana, which refers to hybrids between P. juliae and P. veris.
These so-called Juliana hybrids seem to fall into two groups, those that have retained the creeping, rhizomatous habit of P. juliae, and those which resemble P. veris in their habit.
In the first group fall the "Schnee" hybrids bred by George Arends. The second group includes 'Wanda', 'Garryarde Guinevere', and many other primrose-like cultivars.
What you have there looks more like a polyanthus of some sort, another group of Primula hybrids within section Vernales. Florence Bellis was famous for her polyanthus hybrids, btw.
