Conopholis americana

Conopholis americana
American cancer-root

Secure  (NatureServe)
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Lamiales
Family: Orobanchaceae
Tribe: Orobancheae[1]
Genus: Conopholis
Species: C. americana
Binomial name
Conopholis americana
(L.) Wallr.[2]
Range of Conopholis americana
Synonyms

Orobanche americana L.[3]

Conopholis americana, American cancer-root or squawroot or bear corn, is a perennial,[4] non-photosynthesizing (or "achlorophyllous") parasitic plant, from the family Orobanchaceae and more recently from the genus Conopholis but also listed as Orobanche, native but not endemic to North America and when blooming, resembles a pine cone or cob of corn growing from the roots of mostly oak and beech trees.[5][6]

Description

Conopholis americana is parasitic on the roots of woody plants, especially oaks (genus Quercus) and beech (genus Fagus).[4] The only part of the plant generally seen is the cone-shaped inflorescence,[6] which appears above ground in spring.[7] The entire structure is a yellowish color, turning to brown[4] and achieves heights of 10 centimeters (4 in) to 20 centimeters (8 in) tall.[8]

Stems and leaves

Stout and unbranched 1.3 centimeters (0.5 in) to 2.5 centimeters (1 in) thick stems.[9] Since C. americana does not photosynthesize[6] it also does not have true leaves; it has instead simple, ovate, tiny scales[4] 1.3 centimeters (0.5 in) long and brown, which appear underneath each flower.[8]

Flowers

Conopholis americana produces spikes of yellow to cream flowers densely crowded all around the stem.[8] Each flower is 5-parted, 8 millimeters (0.3 in) to 13 millimeters (0.5 in) long, tubular with a swollen base and facing downwards.[9] As the flowering spike matures and begins to wither and becomes brown throughout the summer and often persisting through the winter, by which time it has become shriveled and black. There is no noticeable floral scent.[8]

Fruits and reproduction

Each flower is replaced by a seed capsule that is longer than it is wide and contains many small seeds. This plant spreads to new locations by reseeding itself.[8]

Roots

The root system is parasitic on the roots of Oak trees (Quercus spp.); dependent on the host tree for its nourishment, the suckers of the parasitic roots cause the formation of large rounded knobs on the roots of the host tree.[8]

Distribution

Found growing on roots in wooded ravines[4] in every state of the United States east of the Mississippi River.[2]

Native:

Nearctic:
Northern America:
Eastern Canada: Nova Scotia, Ontario, Quebec
Northeastern U.S.A.: Connecticut, Indiana, Maine, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, West Virginia
North-Central U.S.A.: Illinois, Wisconsin
Southeastern U.S.A.: Alabama, Delaware, Florida, Georgia, Kentucky, Maryland, North Carolina, South Carolina, Tennessee, Virginia[3]

It is considered an exploitably vulnerable species in New York, a threatened species in New Hampshire and a special concern in Rhode Island.[2]

References

Conopholis americana in beech/oak forest in northern Florida.
  1. ↑ UniProt Consortium. "Species Conopholis americana (Squawroot) (Orobanche americana)". Retrieved 2008-04-13.
  2. 1 2 3 Natural Resources Conservation Service (NRCS). "PLANTS Profile, Conopholis americana". The PLANTS Database. United States Department of Agriculture,. Retrieved 2008-04-13.
  3. 1 2 Germplasm Resources Information Network (GRIN) (2004-03-31). "Taxon: Conopholis americana (L.) Wallr.". Taxonomy for Plants. USDA, ARS, National Genetic Resources Program, National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved 2008-04-13.
  4. 1 2 3 4 5 David Ketzner and Jeanne Karnes. "ILPIN INFORMATION ON Conopholis americana". ILLINOIS PLANT INFORMATION NETWORK. United States Forest Service. Retrieved 2008-04-13.
  5. ↑ Grafton, Emily. "Beech Drops" (PDF). PNPS Notes Quarter #4. Pennsylvania Native Plant Society. 8. Archived from the original (PDF) on February 21, 2007. Retrieved 2008-04-10. External link in |publisher= (help)
  6. 1 2 3 C. Vandaveer (2005-06-27). "Plant of the Week". Archived from the original on 2007-10-24. Retrieved 2008-04-10.
  7. ↑ "Squawroot Conopholis americana". Connecticut Wildflowers. Connecticut Botanical Society. 2008-03-07. Retrieved 2008-04-13.
  8. 1 2 3 4 5 6 John Hilty. "Cancer Root Conopholis americana". Illinois Wildflowers. Retrieved 2008-04-13. External link in |work= (help)
  9. 1 2 University of Wisconsin–Stevens Point. "Conopholis americana (L.) Wallr.". Robert W. Freckmann Herbarium. Retrieved 2008-04-13.
Illustration from 1913.
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