All the years I have been photographing flowers, I was under the impression that Primroses were examples of "unisexual" monoecious flowers where either the stamens or the carpels are missing in all the flowers in a clump. Researching how the primrose ensures an even distribution of 'male' (pin-eyed plants) and 'female' (thrum-eyed plants), I discovered they are in fact bisexual but have different arrangements of the male and female parts - see diagram.
Most of these are taken with a Fuji compact X100 V fitted with a X4 plus a X2.5 diopter close up lens in combination giving very close focus.