Caulophyllum thalictroides (Blue Cohosh)
|Also known as:||Pappoose-root, Squaw-root|
|Habitat:||part shade, shade; moist, rich woods|
|Bloom season:||April - May|
|Plant height:||1 to 4 feet|
|Wetland Indicator Status:||none|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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5 or more stalked flowers in 1 or more loose, branching clusters at the top of the stem. Individual flowers are about ½ inch across with 6 yellowish green petal-like sepals and 6 yellow stamens in a ring around the green center. The true petals are tiny (barely longer than the stamens), greenish, and sit between the sepals and stamens.
Leaves and stem:
Leaves are 3 or 4 times compound in groups of 3, each leaflet to 2½ inches long and wide, toothless and hairless, with 2 to 5 pointed lobes and a short stalk. The base of the leaflet is rounded and often asymmetrical, especially on the lateral leaflets. Non-flowering plants have a single compound leaf, flowering plants have 2.
Blue Cohosh leaves look similar to some other plants, in particular the Meadow Rues (Thalictrum species) but Blue Cohosh has much larger leaflets and the Meadow Rues lack the whorl of leaf and flower stalks at the top of the stem.
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Photos by K. Chayka taken at Wild River State Park, Chisago County. Other photos courtesy Peter M. Dziuk.
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