Kentucky Nature Preserves Rare Plants

Kentucky State Nature Preserves Commission

Armoracia lacustris
Family: Brassicaceae

Protection Status:
State Status:  T
USFWS Status: {null}

Global Rank: G4?
State Rank: S1S2

Quiet shores or muddy waters of sloughs, cypress swamps, seasonal sloughs, or slow water.

Species Description:
Aquatic or subaquatic herb.

Flowering Period: Early May to late August.

Additional Information at NatureServe

Diagnostic Characteristics:
It is distinguished by white 4-petaled flowers, and its size (6 dm above water surface) . The alternate leaves will distinguish it from Ceratophyllum and Myriophyllum and the central stem of the plants distinguish the leaves from those of aquatic Ranunculus and Utricularia. Dimorphic leaves differ on the same plant depending on whether they are submerged or not. The dissected leaves fall off readily when mature and serve as vegetative propagules

Changes in moisture/hydrologic conditions of the habitat for this species would likely be detrimental. Changes could result from overstory removal, stream/wetland alteration or impacts due to erosion or soil deposition.

Global Range:
Armoracia lacustris is found throughout central and eastern United States and southeastern Canada in a variety of aquatic habitats. This species reaches its northern range limit in Quebec and Ontario, Canada, extending southward through Michigan, Indiana, Ohio, Vermont, New York, Maryland, Virginia, Kentucky, Tennessee, and South Carolina to Florida, Georgia, Alabama, Mississippi, and Louisiana and westward to Texas, Oklahoma, Missouri, Illinois, and Wisconsin. Historically, populations also existed in Iowa and New Jersey. It is considered an introduced perennial in Oklahoma (Butler 1993).

Known Kentucky Occurrences:

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Data last updated: Wednesday, May 28, 2014
Kentucky State Nature Preserves Commission
801 Teton Trail
Frankfort,KY 40601
Phone: (502) 573-2886
Fax: (502) 573-2355
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