Toxicodendron radicans (L.) Kuntze
Common Name: POISON-IVY
Coefficient of Conservatism: 2
Coefficient of Wetness: 0
Wetness Index: FAC
Physiognomy: Nt W-Vine

Forests and thickets, both wet and dry, and open ground, both wet and upland.

A vigorous vine climbing by aerial roots, especially in lowland and floodplain habitats, though also sprawling on the ground. It may have spectacular horizontal branches a meter or two long, upturned at the ends, spreading from tree trunks. If there is nothing on which to climb, this can form a rank shrub to 2 m. The leaflets are essentially flat when fresh, ovate to somewhat lance-ovate, and the petioles are pubescent.

This is the commonest source of allergic disease in the United States. Remember that our two poison-ivy species in Michigan are low shrubs or vines, with alternate leaves, whitish fruit, and leaflets entire to sparsely and coarsely dentate and larger than those of most other trifoliolate plants. This species is very local northwards, mainly along the larger rivers. The only other native Michigan vine with such aerial roots is Parthenocissus quinquefolia.

Locations

Allegan County
Arenac County
Barry County
Bay County
Berrien County
Branch County
Calhoun County
Cass County
Clare County
Clinton County
Eaton County
Genesee County
Gratiot County
Hillsdale County
Ingham County
Ionia County
Iosco County
Isabella County
Jackson County
Kalamazoo County
Kent County
Lapeer County
Lenawee County
Livingston County
Macomb County
Manistee County
Mason County
Mecosta County
Midland County
Monroe County
Montcalm County
Muskegon County
Newaygo County
Oakland County
Oceana County
Ogemaw County
Osceola County
Ottawa County
Saginaw County
Shiawassee County
St. Clair County
St. Joseph County
Tuscola County
Van Buren County
Washtenaw County
Wayne County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 12, 2017. http://michiganflora.net/species.aspx?id=99.