Poison Ivy
Poison Ivy
Toxicodendron radicans (L.) Kuntze
Anacardiaceae (Sumac Family)
▲ seedling
▲ young shoots emerging in spring from creeping roots ▲
▲ common "warts" seen on some poison ivy ▲ leaves
▲ ▼ vine climbing a tree
▲ aerial roots from vine that allow it to cling to bark for climbing
▲ ▼ flowering plants
▲ mature fruit
▲ ▼ plants showing their red-orange fall color
Location near campus: growing on and near small garage along alley south of Grand, just east of Kings St.
Toxicodendron radicans (L.) Kuntze; Eastern Poison-ivy: (Bayer Code: TOXRA; US Code TORA2)
- Woody perennial vine or shrub with creeping roots in the Cashew Family (Anacardiaceae)
- Leaves have 3 leaflets; shiny green in summer, sometimes with warts; bright red-orange in fall
- Leaflets may have smooth margins or a few angular teeth
- Clusters of white flowers in spring, followed by white berries by autumn
- Very potent contact dermatitis agent causing itchy sores to develop and spread from point of contact; only takes 20 seconds for protein/allergenic complex to bind to skin; however, not all people develop allergic reactions from contact
- All parts of plant contain a contact poison (urushiol) that causes itching, and development of fluid-filled pustules on the skin (eyes, mouth, lungs, etc.) of sensitive people/animals; plant is poisonous when dormant as well as when actively growing; even smoke from burning stems and leaves can cause allergic reaction inside lungs
- In Missouri, this is the main species present; poison oak species are not known, or at least not common
- Another poison ivy sometimes listed as a separate species:
- Toxicodendron rydbergii (Small ex Rydb.) Greene; Western Poison-ivy: (Bayer Code: not known; US Code TORY)
- Some list western poison-ivy (Toxicodendron rydbergii) as a separate species from eastern poison-ivy (Toxicodendron radicans), that only forms colonies of 2-4 foot tall, single-stemmed or few-branched plants arising from spreading rhizomes--it does not climb as a vine--but stem, leaf and fruit characteristics are similar to Toxicodendron radicans, so some botanists believe they are the same species
(Updated January 15, 2019)