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One-flowered Broomrape ; One-flowered Cancer Root, Ghostpipe, Naked Broomrape - Orobanche uniflora


Family: Orobanchaceae - Broom-rape family Genus Common Name: Broomrape Native Status: Native
Orobanche uniflora - One-flowered Broomrape ; One-flowered Cancer Root, Ghostpipe, Naked Broomrape. Not having knowingly encountered this parasitic plant previously, I was surprised to find that it is found in every state in the United States except for Hawaii. It's also found in much of Canada. It may attach its feeder roots to the roots of many different species of plants.

Plants of the genus Orobanche are classified as a noxious weed or similar pest plant in the United States federally and in 9 states specifically, but there is an exception for native species in all cases but two states (Massachusetts and Florida), and Florida specifically excludes Orobanche uniflora from its noxious weed list, which leaves only Massachusetts with a negative classification for One-flowered Broomrape.

An explanation of the somewhat unfortunate name is probably appropriate. "Broom" is an old-world name for vetches and other similar legumes, which are among the plants which Orobanche parasitize. A "rapum" is a term for a knob of roots, to which Orobanche attach to perform their nefarious parisitic activities.

Synonyms: Thalesia uniflora, Aphyllon uniflorum, Orobanche porphyrantha, Orobanche purpurea, Orobanche sedii, Orobanche terrae-novae. Weakley still classifies this plant as Aphyllon uniflorum in his esteemed Flora of the Southern and Mid-Atlantic States (2015).

Found in:
AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, 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

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Orobanche uniflora

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

Map from USDA Plants Database:
USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov, 25 Feb 2017). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

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Site: Boise Foothills, Ada County, ID Date: 2011-June-21Photographer: Gerald C. Williamson
Nikon D7000
Tamron SP 90MM f/2.8 AF Macro
Since this is a parasitic plant, it does not contain clorophyll, so there are no green leaves. The plant may grow up to 10 tall, and may produce up to 5 flowering stalks which are usually hairy. There is a single flower per stalk.
Orobanche uniflora

Site: Boise Foothills, Ada County, ID Date: 2011-June-21Photographer: Gerald C Williamson
Nikon D7000
Tamron SP 90MM f/2.8 AF Macro
The single blossom per stalk is white to pale purple, and is about an inch long.
Click on the photo for a larger image
Orobanche uniflora

Site: The Pocket at Pigeon Mountain, Walker County, GA Date: 2016-April-14Photographer: Gerald C Williamson
Nikon D7000
Tamron SP 90MM f/2.8 AF Macro
Orobanche uniflora is a widely distributed species in North America. This photo is from northwest Georgia; the others are from southwest Idaho, 2,000 miles apart.
Click on the photo for a larger image
Orobanche uniflora

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All content except USDA Plants Database map Copyright Gerald C. Williamson 2017
Photographs Copyright owned by the named photographer