Polymnia canadensis (Leafcup)

Plant Info
Also known as: White-flower Leaf-cup
Family:Asteraceae (Aster)
Life cycle:perennial
Habitat:part shade, shade; moist, rich woods, ravines
Bloom season:June - September
Plant height:2 to 5 feet
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: 5-petals Flower shape: 6-petals Flower shape: 7+petals Cluster type: raceme

[photo of flowers] Nodding clusters at the tips of branching stems, each with 2 to 5 stalked flower heads. Flower heads are 1/3 to ½ inch across typically with 5 to 8 white rays (petals) that are quite short and have 3 small lobes at the tip. Flowers in the center disk are creamy white to pale yellow. Occasionally the ray flowers are unlobed, or as long as or longer than the center disk, or absent altogether.

[photo of glandular hairy bracts] The bracts (phyllaries) surrounding the base of the flower are in 2 series. The outer are very narrow and curl back (recurved), the inner are broader and usually shorter than the outer. Phyllaries and flower stalks are densely hairy, often glandular.

Leaves and stems: Leaf attachment: opposite Leaf type: lobed Leaf type: simple

[photo of leaves] Leaves are opposite, 4 to 10 inches long, up to 5 inches wide, broadly lance-oblong in outline, typically with 3 to 11 deep, irregular and angular lobes, though uppermost leaves may be smaller and unlobed. Edges are minutely to coarsely toothed and fringed with short hairs; surfaces are variably hairy, more so along major veins on the underside. The base of the blade sometimes extends down the leaf stalk, creating broad, irregular wings.

[photo of stipules (underside)] At the base of the leaf stalk is a pair of leafy appendages (stipules) that are hemispheric in outline, shallowly lobed, coarsely toothed and hairy. Leaf stalks are hairy and up to 4 inches long. Stems are erect, branched in the upper plant, densely hairy and often glandular.

Fruit: Fruit type: seed without plume

Fruit is a dry seed without a tuft of hairs.


Leafcup reaches the northwest tip of its range in Minnesota and is a plant of damp, shady woodlands and ravines. The leaves are somewhat similar to Appendaged Waterleaf (Hydrophyllum appendiculatum), which may be found in the same habitat, but has leaves with fewer and usually shallower lobes (lower leaves in particular), and 5-petaled saucer to bell-shaped lavender flowers.

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More photos

Photos by K. Chayka taken at Whitewater Wildlife Management Area, Winona County. Photos courtesy Peter M. Dziuk taken in Fillmore, Houston and Winona counties.


Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Brian - Cannon River Trout Lily SNA, Rice Lake SP, River Bend NC
on: 2018-02-25 09:59:40

I've seen leafcup at the base of the main outcrop in the western part of Cannon River Trout Lily SNA (growing along with Hydrophyllum appendiculatum), in woods along the north shore of the lake in Rice Lake State Park (very abundant), and a few plants along the main north-running trail in the southern part of River Bend Nature Center in Faribault.

Posted by: Mary Winnett - Forestville/Mystery Cave State Park
on: 2019-08-24 11:39:22

I saw this on the hiking club trail,, in the "Maple Canopy" part of the trail

Posted by: Sara Brice - Wilderness Park in Rice County
on: 2021-08-03 23:18:24

This is strikingly prevalent in areas along the upper trail at Wilderness Park West where the tree blowdowns have allowed more sunlight.

Posted by: margot Rideaux - Burnsville
on: 2021-08-16 15:29:14

Last summer this plant popped up in a shady spot. This summer, it bloomed. The stems are purple. It seems very invasive.

Posted by: K. Chayka
on: 2021-08-17 07:41:22

Margot, I have never heard of this being a problem plant. Perhaps you have something else. Post some images on the Minnesota Wildflowers Facebook page if you'd like confirmation.

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