Oxypolis rigidior (Cowbane)

Plant Info
Also known as: Common Water Dropwort
Family:Apiaceae (Carrot)
Life cycle:perennial
Habitat:part shade, sun; wet prairies, fens, sedge meadows, swamps, marshes
Bloom season:July - August
Plant height:2 to 5 feet
Wetland Indicator Status:GP: OBL MW: OBL NCNE: OBL
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 Cluster type: flat

[photo of flowers] Flat clusters (umbels) 3 to 6 inches across made up of 10 to 25 groups (umbellets) of up to 25 flowers each. Flowers are about 1/8 inch across with 5 white petals notched at the tip, on slender, hairless stalks up to ¾ inch long. 5 white stamens radiate from the greenish white ovary in the center.

[photo of bracts] Up to 3 thread-like bracts are at the base of an umbellet, though not all umbellets have bracts. Likewise, umbels may have up to 3 narrow bracts at the base, or none.

Leaves and stems: Leaf type: compound

[photo of dentate leaves] Leaves are few, alternately attached, compound with 5 to 11 leaflets, 12 inches long or more on the lower stem becoming somewhat smaller as they ascend the stem. Leaflets are 1½ to 4 inches long, 1/8 to 1 inch wide, lance-linear to oblong-elliptic, hairless, and stalkless. Leaflet edges may be toothless, have a few, widely spaced teeth, or have a few narrow, tooth-like projections (dentate) toward the tip.

[photo of stem and leaf node] Leaf stalks form a narrow sheath that rings the stem. Stems are stout or slender, hairless, lined or weakly ridged, and unbranched or few branched.

Fruit: Fruit type: seed without plume

Fruit is about ¼ inch long, flattened, oval, ribbed, and splits into 2 seeds.


Cowbane is one of the several white-flowered carrot species found in moist to wet places. It is most similar to Water Parsnip (Sium suave), which has 6 to 10 bracts at the base of each umbel and leaflets that are finely serrated all around the edges. Water Hemlock (Cicuta maculata) also has serrated leaflets, and its leaves are twice compound. Cowbane is far less common than these two species; while not currently listed as a rare species, it is not often encountered in the wild and is tracked by the DNR.

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More photos

Photos courtesy Peter M. Dziuk taken in Dakota County.


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

Posted by: Kenny h - East of rose creek on shooting star trail
on: 2017-07-23 07:52:37

I found this growing next to Tuberous Indian Plantain...I have photographed it in the past...thankyou Mn Wildflowers for making plant ID so much easier.

Posted by: Vicky - Lake Minnetonka
on: 2019-08-19 21:44:52

The MN Dept of Agriculture has suggested a plant I have on our property may be cowbane based on pictures I sent to them. Is this poisonous and does it need to be removed? Your note says the DNR tracks this plant. Can you tell me if I should be notifying someone about this or if someone can positively identify the plant on our property? There appears to be more on my neighbor's property. Thank you

Posted by: K. Chayka
on: 2019-08-21 08:52:54

Vicky, we don't know who specifically in the DNR would be interested in this information. The word "bane" in the common name indicates it's toxic, at least to cows. It is not officially a rare species and since it's on private property you may deal with it as you like.

Posted by: K Hill - Hinckley
on: 2022-08-02 10:56:13

Growing along our pond shores.

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