Q: While on vacation in Colorado, I found groves of these growing just below the tree line. Can you identify?
A: It’s false hellebore, a.k.a. skunk cabbage, Veratrum tenuipetalum. It is not a true skunk cabbage, Symplocarpus foetidus (Eastern skunk cabbage) or Lysichiton americanus, Western skunk cabbage).
False hellebore is quite poisonous.
See False Hellebore