Toxicodendron rydbergii (Poison Ivy) - photos and description



Fuzz from nearby aspen trees going to seed.

 


Plant against tree has flower buds unopened.

 

 

General: Low, erect shrub (its lowest stem is woody), rhizomatous. This plant is well known for causing painful blisters to many people who touch it. There is an old saying to remember - "Leaves of three, let it be".

I hate this plant. I'm very susceptible to Poison Ivy's toxins. It's given me red, very itchy blisters several times on the wrists and hands, or ankles while photographing plants or hiking and being unaware of its presence. My own experience is the blisters begin to show up 24-36 hours after exposure and persist for about a week. Wildflowers Across the Prairies states that all parts of the plant may exude enough toxin to affect susceptible persons.

Flowers: Flowers are greenish-white, in dense panicles in leaf axils. Petals are recurved, 5 in number, and there are 5 orange-yellow stamens. I measured a flower at 4 mm diameter.

Leaves: Leaves are alternate, trifoliate on long petioles. Leaflets are dark green and often shiny on their top surface and lighter green on their bottom surface. Leaflets are ovate, have a few irregular teeth and a sharp tip. I measured a leaflet at 10 cm long by 7 cm wide. There are very short hairs on the nerves on top of leaflets, and soft, longer hairs on bottom of leaflets.

Height: Height listed in Budd's Flora to 30 cm. I measured plants to 49 cm tall.

Habitat: Ravines, shady woodlands, sandy hills. Very prevalent on the wooded slopes of the Qu'Appelle Valley.

Abundance: Common.

Origin: Native.

Synonym: Listed in some of the field guides we use as Rhus radicans.

When and where photographed: The above photos were taken June 8th and June 15th, steep wooded slopes at Fairy Hill, 30 km north of our home in Regina, SK.