Toxicodendron rydbergii

Posted 7 December 2015 by Matt Young

Toxicodendron rydbergii -- western poison ivy, South Boulder Creek Trail, Boulder, Colorado, September, 2015. Poison ivy is red only in the fall.

2 Comments

Marilyn · 8 December 2015

Could be a representative of the angels sword.

Kevin B · 10 December 2015

Poor Per Axel Rydberg.

Johannes Rydberg gets a whole set of things in physics named after him.

Per Axel gets a toxic plant.....