Is this a berry, a seed or something else altogether?

It is, in fact, a wingless scale insect that lives on the Scarlet Oak tree of southern and eastern Europe.

Historically, it was a very important crimson dye. The Ancient Egyptians imported it from Mesopotamia, but trade routes covered the known world, from Europe to China. When it was ruled by Ancient Rome, half of Spain’s taxes to the capital were in the form of kermes.

The insect was harvested by scraping carefully from the branches with the ngernails. The red colour is extracted by crushing the resin-encrusted insects and boiling them in lye.

Its name comes from the Sanskrit krim-dja (derived from a worm). In Hebrew it was tola’at shani (worm scarlet). Kermes is the linguistic root of the English crimson and carmine.

In medieval Europe kermes was called baca (‘berry’). Alongside another insect red of the Middle Ages called granum (grain) it shows how misunderstood the origin of the colour was. Chaucer refers to a cloth that is ‘dyed in grain’, meaning dyed crimson. Because of the strong, lasting nature of this colour, the phrase came simply to mean deeply or permanently dyed.

With the discovery of the New World in the 15th C, Kermes was superseded by the stronger red of Cochineal, to which it is related. By the 1870s Kermes had all but completely disappeared from use.