Al Schneider's Rocky Mountains Plant Descriptions

Western Poison Ivy
Toxicodendron rydbergii
Sumac family (Anacardiaceae)

"Leaves of three, let them be" is the adage for avoiding Poison Ivy. The plant is poisonous and contact with bruised or broken leaves and stems causes mild to severe skin irritation. Best cure is avoidance, but if you think you have come into contact with the sap, flood with water, wash with soap, or wash immediately with one of several commercially available lotions designed to effectively break down the oils. The plant is toxic even in the winter. The plant is named for Per Axel Rydberg (1860-1931), one of the most respected botanists of his time.


©2007 Russ Kleinman, Western New Mexico
University Department of Natural Sciences and the
Dale A. Zimmerman Herbarium

Description

shrub, trailing to erect or vine, 3-8" tall, with leaves divided into 3 with pointed tips and to round- or margins. Leaves vary from dull light green to shiny deep green. Veins prominent on underside of leaf. Clusters of tiny flowers arise from leaf axils before leaves appear. are white-green -life . Leaves turn red, orange, and yellow in late summer, early fall.

Field Marks

3 egg-shaped, pointed, slightly , green ; white .

© Al Schneider

An entire leaf has smooth edges. Not toothed or lobed.

lobe -- Being divided by clefts.

serrate -- toothed with asymmetrical teeth pointing forward; like the cutting edge of a saw.

ovate -- Oval, egg-shaped, with a tapering point.

Like the teeth on a saw, leaves and other surfaces can have toothed edges.

Deciduous plants are those that lose all of their leaves for part of the year.

fruit -- any seed-bearing structure in flowering plants. It is formed from the ovary after flowering.

The botanical term "berry" is different from common usage. Strawberries and raspberries are not berries. But a tomatoe is. A true berry is a fruit with the seeds immersed in the pulp.

drupe -- A fruit in which an outer fleshy part surrounds a hardened shell containing a seed. A peach is a drupe. A raspberry is composed of drupelets.

alternate -- leaves alternate along the main stem and are attached singly.

leaflets -- Each little leaf-like thing in a compound leaf is a leaflet.