This clue gave us the night, for though you can see the moon on clear days in the early evening and just after dawn, it is at its best, and brightest, in the darkness of the night.
As for the flower, that is the Marvel of Peru, or Mirabilis Jalapa, or the Four o'Clock Flower, because the flowers tend to open at dusk (usually between 4 and 8 o'clock). And though here it is shown in the white form, for some reason, it does come in a range of colours, yellow, pink and white being the most common
This is an unusual subject, and its dark colours make it really stand out amongst the other sets. You may think that night flowers, or nocturnal flowers, are also rare, but they are surprisingly common, their scents designed to appeal to such insects as moths and flies, but also to bats, and beetles. After all, night technically begins at dusk, when many creatures are on their way home, or just beginning to stir for a new night`s adventure.
The flowers included are also more familiar than you might imagine, they are :
- Cereus Grandifloreus (night blooming cactus)
- Jacinthe Tubereuse (tuberous hyacinth)
- Julienne (night scented gilliflower)
- Merveille du Perou (Belle de Nuit)
- Oenothere des Pres (evening primrose)
- Victoria Regie (Amazonian water lily)
This set was issued in several versions. The ones you are most likely to come across are in Belgian or French (both as the same title, of "Fleurs de Nuit"), German, ("Nachtblutler"), or Italian ("Fiori de Notte"). The Dutch version, called "Nachtbloemen", is a fair bit rarer though.