Named in Hortulus
Wormwood
Artemisia absinthium
What was written
Walahfrid includes wormwood among his plants, where it carried the reputation for bitterness that made its name proverbial across medieval Europe. Its later fame is secular rather than monastic: it is the plant that gives absinthe both its name and its character.
What is now known
Wormwood contains thujone, a neurotoxin. Sustained or concentrated exposure causes seizures, and food law in the EU limits how much thujone a product may contain precisely because of it.
The plant itself
A silver-grey perennial of the daisy family, reaching about a metre, with finely divided foliage covered in silky hairs that give the whole plant its pale cast.
Still growing
Since the plant was written into that garden list, botanists, herbaria and ordinary observers have recorded finding it 109,695 times.
Live count from GBIF, cached for a week.