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Black Medic, Black Hay, Hop Clover, Hop Medic, Yellow Trefoil - Medicago lupulina


Family: Fabaceae - Pea family Genus Common Name: Alfalfa Native Status: IntroducedDicot Annual Perennial Herb
Medicago lupulina - Black Medic, Black Hay, Hop Clover, Hop Medic, Yellow Trefoil. This plant is a native to Eurasion and Africa, and after introduction to the United States has spread to every state, and also throughout most of Canada. Clearly is appropriately considered invasive.

The leaves are trifoliate, looking very much like those of species in the Trifolium (Clover) genus. As with Trifolium campestre the stem of the terminal leaflet is longer than those of the lateral leaflets. Leaflets of Medicago have a tiny tooth at their apex; those of Trifolium do not.

Found in:
AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY
Medicago lupulina

Distribution of Medicago lupulina in the United States and Canada:
USDA Map temporarily unavailable.
Blue=Native; Grey=Introduced

Map from USDA Plants Database:
USDA, NRCS. 2017. The PLANTS Database (http://plants.usda.gov, 16 Jan 2025). National Plant Data Team, Greensboro, NC 27401-4901 USA.

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Site: Ada County, ID Date: 2010-June-07Photographer: Gerald C. Williamson
Nikon D60
Tamron SP 90MM f/2.8 AF Macro
I had this image misidentified as Trifolium campestre while it is actually Medicago lupulina. Thanks to Robert Flogaus-Faust for bringing my attention to this incorrect identification. There is a slight difference in the floret shape as well as in the leaf structure.

The fruit of the plant turns black, influencing the common names.
Medicago lupulina
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Medicago lupulina initially published on USWildflowers.com 2013-02-12; Updated 2015-06-25

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