Western Poison Ivy (Toxicodendron rydbergii): green Minnesota wildflowers

Western Poison Ivy

Plant Info
Also known as:
Scientific name:	Toxicodendron rydbergii
Family:	Sumac (Anacardiaceae)
Life cycle:	perennial
Origin:	native
Habitat:	sun to part sun; edges of woods, prairies, open areas
Bloom season:	late spring, summer
Plant height:	6 to 36 inches
USDA PLANTS database:	Minnesota county distribution map
Spotted in Ramsey County at:	Long Lake Regional Park Vadnais/Snail Lake Regional Park

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Detailed Information

Flower:: Flowers are in branching spike-like clusters that arise from the leaf axils. Each flower is about 1/16 inch across, 5 greenish white petals and 5 stamen with yellow-orange tips, though they are difficult to see. The spikes may be from 2 inches to over a foot long.
Leaves and stem:: Leaves are compound in groups of 3, each group at the end of a long stem alternately attached on the woody main stem, usually near the top. The leaves spread out over the flowers like an umbrella, often hiding the flowers from view. Each leaflet is up to 6 inches long and 4½ inches wide, generally oval, usually with an abrupt sharp point at the tip and slightly tapering at the base. Some leaves have a few notches on the side, looking like very large teeth. The leaf surface is a bit shiny.
Fruit:: Fruit is a smooth, round, dull white to yellowish berry about 1/8 inch in diameter. The berries persist through the winter (this photo taken in January).
Notes:: Western Poison Ivy is on the noxious weed list for Minnesota due to its toxic, rash-producing properties, as well as its somewhat aggressive growth. It is actually categorized as a shrub because of the woody main stem. It is not to be confused with other plants having leaves in 3's on long stems: Jack-in-the-pulpit, various species of Trillium, or Wild Sarsaparilla. Poison Ivy's woody main stem is a distinguishing feature, the vein pattern and/or shape of the leaves is different than those other plants, and the flowers are easily recognizable when the plant is in bloom.