This is false oxlip (Primula x polyantha (vulgaris x veris)), a frequent natural hybrid of primrose (Primula vulgaris) and cowslip (P. veris), and the only sort of oxlip you are ever going to see in the UK, unless you go to the curiously restricted area in Cambridgeshire/Suffolk where the true oxlip (P. elatior), which has a one-sided nodding umbel, completely replaces the primrose. [nb. Peter Llewellyn, whose ukwildflowers website is strongly recommmended, says that the above piece of information, derived from Stace, appears to be untrue; in Waresley Wood Cambs, primroses grow alongside the oxlips and frequently hybridize, producing Primula x digenea (vulgaris x elatior).]
Philologically, however, it seems that the English word "oxlip" was originally applied to the primrose/cowslip hybrid pictured above, not to the species. It is obviously just a folk-masculinization of cowslip, referring to its larger flowers. The second part of these attractive names comes from "slyppe", OE for slimy poo, in other words a fresh cowpat or cowslop.
So in this case "ox" means a male cow. What is odd and nearly unique about these animals is that they don't really have a common non-gender-specific kind-name in the singular - there's no equivalent to horse, pig or sheep. We just call them cows (if female) or bull (if male). "Ox" would pass, according to the dictionary, though this can also mean a castrated male, and anyway it certainly has no place in common idiomatic English. "Cattle" is plural and anyway is not strictly limited to them but to all pasture animals. In France the kind-name is boeuf. Among farmers this French usage sometimes re-emerges: "It was a surprise to me that none of the beef was finished on grass". The other animal that doesn't have a non-gender-specific kind-name is us. "Man" is rightly not acceptable now, and in its ancient use was gender-specific, in my opinion: women were simply exluded from the kind of academic or theological discourse in which "Man" was used, as a matter of little concern. The short intervening period in which "Man" was taken up as consciously meaning "men AND women" was always conflicted and unstable, always tending to drop back into frank medieval chauvinism, never quite managing to connote what the academic community wanted it to denote.
"Primrose", another pretty name, seems to have developed by a sort of false etymology from "primerole". According to this etymology it would then mean the prime or first "rose" of the year. The flower-shape, because of its notched petals, does after all strongly resemble the shape of a natural rose such as the sweetbriar, the type of all flowers and all beauty in the folk-imagination.