Claim: The soils are humic or loamy, well drained and acid  with a pH of 5.5 – 5.8; the moss (Ditrichum cornubicum or Cornish path-moss) likes a metal-rich substrate with concentrations of copper of 151 – 1400 parts per million (ppm).
Evidence: Ditrichum cornubicum, commonly known as the Cornish path-moss, is a moss endemic to Cornwall, United Kingdom. The soils are humic or loamy, well drained and acid with a pH of 5.5 – 5.8. It likes a metal-rich substrate with concentrations of copper of 151 – 1400 parts per million (ppm).