Named in Hortulus
White horehound
Marrubium vulgare
What was written
Horehound is one of the plants Walahfrid grew. It is bitter enough that its presence in a garden is difficult to explain by taste, and it held a place in European herbals continuously from the classical period into the nineteenth century — long enough that Köhler's Medizinal-Pflanzen still gave it a plate in 1887.
The plant itself
A grey, woolly perennial of the mint family, growing on dry stony ground, with wrinkled leaves and small white flowers set in tight whorls around the square stem.
Still growing
Since the plant was written into that garden list, botanists, herbaria and ordinary observers have recorded finding it 125,136 times.
Live count from GBIF, cached for a week.