• Wind Cave National Park - Two Worlds

    Wind Cave

    National Park South Dakota

Seed Study - Cirsium undulatum

Cirsium undulatum - Wavy Leaf Thistle

Cirsium undulatum - Wavy Leaf Thistle

NPS Photo

Species: Cirsium undulatum
Common name: wavy leaf thistle

Seedling Identification: These seedlings look very similar to Scotch thistle (Onopordum acanthium) seedlings. However the first leaves of wavy leaf are less lobed and have very fine spines off the leaf edges.


Cirsium undulatum – wavyleaf thistle
Average number of good seeds per gram bulk matter: n.m.
Average number of good seeds per gram cleaned: 109 (46)
Commercial estimates of seeds per gram: n.a.
Percent seed: n.m.
Percent live: 67
Collection dates: July 20; August 16; October 6 and 20
Collection effort: 40 grams in 5 person hours
Collection notes: Relatively common and easy to collect however it tends to have a lot of insect damage.
Cleaning notes: Most appeared to be pure seed however a few might have been buggy or empty.

Did You Know?

fire on the prairie

Fire is an important factor in protecting the prairie. Historically, fires burned across the prairie every 4 to 7 years. Fires burn the small trees that would otherwise march across the prairie and turn the grasslands to forest.