Eupatorium mohrii

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Eupatorium mohrii
Eupa mohr.jpg
Photo by Dennis Girard, Atlas of Florida Vascular Plants
Scientific classification
Kingdom: Plantae
Division: Magnoliophyta - Flowering plants
Class: Magnoliopsida – Dicotyledons
Order: Asterales
Family: Asteraceae ⁄ Compositae
Genus: Eupatorium
Species: E. mohrii
Binomial name
Eupatorium mohrii
EUPA MOHR dist.jpg
Natural range of Eupatorium mohrii from USDA NRCS Plants Database.

Common name: Mohr's thoroughwort; Mohr's Eupatorium

Taxonomic notes

Synonyms: none[1]

Varieties: none[1]


A description of Eupatorium mohrii is provided in The Flora of North America.


This species is distributed from southeast Virginia south to southern Florida and west to Texas.[1]



Generally, E. mohrii can be found in moist savannas as well as other wet habitats.[1] Native, perennial herb in longleaf pine stands.[2] It does well in open canopy areas on longleaf pine habitats. Does not do well in highly disturbed areas (such as clear cutting).[3] It is found areas that have become wet in some parts of the year such as in slash pine flatwoods, hammocks, near creeks, pond-pine scrubs, peaty pine savannas, wet flatwoods, swampy depressions between sand ridges, pine-palmetto flatwoods, upper edges of hillside bogs, edges of titi bogs, swales and dunes, and in river floodplains. It is also found in human disturbed areas such as pinelands that have been clear cut, along roadside depressions, embankments, edges of an artificial pond, and in powerline corridors. It is associated with areas that have moist soil, moist sandy peaty soil, semi-wet soil, muckly aulluvium soils, and moist sandy clay.[4]

Associated species include Eupatorium rotundifolium, E. album, E. cuneifolium, E. leucolepis, E. recurvans, E. mikaniodes, Andropogon, Aster dumosus, Ludwigia virgata, Carex joorii, Panicum rigidulum, Rhexia mariana, Rubus cuneifolius, Magnolia virginina, Pinus palutris, P. elliottii, P. taeda, Serenoa repens, Aristida stricta, Quercus, Liquidambar styraciflua, Cyrilla racemiflora.[4]

Eupatorium mohrii is an indicator species for the Peninsula Savannas community type as described in Carr et al. (2010).[5]


E. mohrii generally flowers from August until October.[1] It has been observed flowering from June to November.[6][4]

Seed bank and germination

Seeds of Eupatorium mohrii were found to persist in the seed bank after a fire disturbance. It is normally found in the seed bank, but is not as prevalent as other species.[7]

Fire ecology

This species commonly occurs in pinelands that are fire-dependent.[8] The seeds of this species have also been found to persist in the seed bank even after a fire disturbance.[7]


Eupatorium mohrii has been observed at the Archbold Biological Station to host wasps such as Pachodynerus erynnis (family Vespidae), thread-waisted wasps from the family Sphecidae such as Bicyrtes capnoptera, B. insidiatrix, Cerceris blakei, Philanthus ventilabris, Prionyx thomae, Tachytes pepticus, and T. validus, leafcutting bees from the family Megachilidae such as Coelioxys mexicana, Dianthidium floridiense and Megachile albitarsis, wasps from the family Leucospididae such as Leucospis robertsoni, and L. slossonae, sweat bees from the family Halictidae Agapostemon splendens and Halictus poeyi, and bees from the family Apidae such as Apis mellifera, and Bombus impatiens.[9] Other pollinators in the Hymenoptera order include Halictus ligatus.[10] E. mohrii also attracts various butterflies as a nectar source for pollination.[11] Thick-headed flies in the genus Physoconops were collected from the flowers of E. mohrii and possibly pollinate the plant as well.[12]

Conservation, cultivation, and restoration

Cultural use

Photo Gallery

References and notes

  1. 1.0 1.1 1.2 1.3 1.4 Weakley, A.S. 2020. Flora of the Southeastern United States. Edition of 20 October 2020. University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
  2. Harrington, T. B. (2011). "Overstory and understory relationships in longleaf pine plantations 14 years after thinning and woody control." Canadian Journal of Forest Research 41: 2301-2314.
  3. Brockway, D. G. and C. E. Lewis (2003). "Influence of deer, cattle grazing and timber harvest on plant species diversity in a longleaf pine bluestem ecosystem." Forest Ecology and Management 175: 49-69.
  4. 4.0 4.1 4.2 Florida State University Robert K. Godfrey Herbarium database. URL: Last accessed: June 2014. Collectors: R.K. Godfrey, Loran C. Anderson, A. F. Clewell, Clarke Hudson, R.L. Lazor, J. P. Gillespie, D. S. Correll, P. L. Redfearn, Jr., Sid McDaniel, J. Lazor, Jean W. Wooten, V. I. Sullivan, J. Britten, B. K. Holst, Cruz, Montero, C. Jackson, R. Kral, Roomie Wilson, B F Hansen, JoAnn Hansen, Carol Havlik, Ann F. Johnson, Chet Winegarner, Marsha Winegarner, S. C. Hood, R. A. Norris, R. Komarek, and Annie Schmidt. States and Counties:Florida: Bay, Brevard, Citrus, Clay, Columbia, Dixie, Flagler, Franklin, Gulf, Hamilton, Holmes, Jefferson, Leon, Levy, Liberty, Martin, Okaloosa, Putnam, Santa Rosa, Sarasota, St. John’s, Suwannee, Taylor, Union, Wakulla, Walton, and Washington. Georgia: Atkinson, Brantley, Camden, Charlton, Clinch, Decatur, Echols, Grady, Thomas, and Ware.
  5. Carr, S.C., K.M. Robertson, and R.K. Peet. 2010. A vegetation classification of fire-dependent pinelands of Florida. Castanea 75:153-189.
  6. Nelson, G. PanFlora: Plant data for the eastern United States with emphasis on the Southeastern Coastal Plains, Florida, and the Florida Panhandle. Accessed: 9 DEC 2016
  7. 7.0 7.1 Kalmbacher, R., et al. (2005). "Seeds obtained by vacuuming the soil surface after fire compared with soil seedbank in a flatwoods plant community." Native Plants Journal 6: 233-241.
  8. Carr, S. C., et al. (2010). "A Vegetation Classification of Fire-Dependent Pinelands of Florida." Castanea 75(2): 153-189.
  9. Deyrup, M.A. and N.D. 2015. Database of observations of Hymenoptera visitations to flowers of plants on Archbold Biological Station, Florida, USA.
  10. Deyrup, M. J. E., and Beth Norden (2002). "The diversity and floral hosts of bees at the Archbold Biological Station, Florida (Hymenoptera: Apoidea)." Insecta mundi 16(1-3).
  11. [[1]] Lady Bird Johnson Wildflower Center. Accessed: May 10, 2019
  12. Clouse, R. M., et al. (1997). "Observations of insects associated with an infestation of sand pine (Pinus clausa) by the aphid Cinara pinivora." Florida Scientist 60(2): 89-93.