False Hellebore
  or Corn Lily
(Veratrum californicum)

These striking plants grow four or five feet tall. They have large leaves, with parallel veins which look like pleats or ridges. They grow in wet meadows, and stand above the surrounding vegetation. The plants (especially the roots and young shoots) contain alkaloids, which can be poisonous to livestock.

This plant is also called Skunk Cabbage.