Most flowers need a dictionary. The forget-me-not carries its message in its name, which is why its meaning has barely moved in five hundred years.

The English name appears in the 1530s as a translation of the Old French ne m'oubliez mye, "don't forget me". Already in the fifteenth century, according to the Online Etymology Dictionary, the flower was supposed to make sure that whoever wore it would never be forgotten by a lover. Other languages made the same translation: German Vergissmeinnicht, Swedish förgätmigej, Czech nezabudka.

So when the Victorian flower books came to it, there was not much to invent. Henrietta Dumont's 1851 Language of Flowers simply repeats the name: "Forget me not." Kate Greenaway's 1884 list, now free on Project Gutenberg, gives "True love. Forget me not." This is one of the few flowers on which the old books, which usually disagreed with each other, speak with one voice.

In the twentieth century the meaning widened from lovers to the dead. In Newfoundland and Labrador people wear forget-me-nots around 1 July to remember those killed at Beaumont-Hamel on the Somme and in the First World War more widely. In Germany the flower is used to commemorate fallen soldiers. In 2015 it was chosen as the emblem of the centenary of the Armenian Genocide, and in the Netherlands it is the symbol of Alzheimer Nederland. Each is the same request the flower has always made.