Toxicodendron rydbergii By Matt Young December 7, 2015 12:00 MST Toxicodendron rydbergii – western poison ivy, South Boulder Creek Trail, Boulder, Colorado, September, 2015. Poison ivy is red only in the fall.
Toxicodendron rydbergii – western poison ivy, South Boulder Creek Trail, Boulder, Colorado, September, 2015. Poison ivy is red only in the fall.
