Belinuncia

Belinuncia in Gallic mythology, was a poisonous plant, possessing a magic effect, sacred to Belenus or Belinus, from whom its name. The Gauls poisoned their arrows and lances with it. It was also said to produce rain and stormy weather, if dug up by a virgin at midnight during the new-moon, while if gathered during the full-moon it produced aridity.