Eyebright – Euphrasia spp.

eyebright

Overall At-Risk Score: 40

Latin Name:

Euphrasia spp. is a genus of roughly 450 species of annual herbs. Species confirmed to live in North America include E. × aequalis, E. disjuncta, E. frigida, E. hudsonia, E. micrantha, E. mollis, E. nemorosa, E. oakesii, E. randii, E. stricta, E. subarctica, E. suborbicularis, E. tetraquetra, and E. vinacea.

Common Name:

Eyebright

Family:

Orobanchaceae (Broomrape family)
(Formerly Scrophulariaceae, the figwort family)

Lifespan:

Annual

Reproduction:

Being an annual, this plant must reproduce from seed each growing season. Its establishment each year also depends heavily on the perennial regeneration of its host plants. Euphrasia can have difficulties in reproduction due to a low rate of seed germination.

Geographic Region:

Eyebright grows in portions of nearly every region in the Northern Hemisphere, though it only grows in a few states in the U.S., namely Alaska, Connecticut, Illinois, Maine, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, New York, Oregon, Pennsylvania, Rhode Island, Vermont, Washington, and Wisconsin.

Habitat:

Euphrasia lives primarily in deciduous forest margins, or dry fields, though they are also found along roadsides and waste areas, and specific species have their own requirements for the land they can inhabit. Where eyebright plants live depends largely upon the plants around it, as Euphrasia is a hemiparasitic plant that thrives when using nutrients gained by connecting its root systems to nearby plants through their haustorium—specialized root-like filaments that latch onto the preexisting roots of other plants to leech water and nutrients from them.

Vulnerability of Habitat/Changes of Habitat Quality and Availability:

In experiments on Euphrasia cultivation, Euphrasia was found to be very sensitive to proper soil composition and moisture levels, as well as temperature and light changes. Abiotic stress is a major concern regarding the wellbeing of this genus. Additionally, though the plant is capable of surviving without parasitizing off other species, eyebright plants are more likely to survive if they have access to a variety of hosts, and thus changes to the biodiversity of a region could impact the long term health of a Euphrasia population.

Status of Endangered/Threatened (by state):

E. disjuncta is listed as “Possibly Extirpated” in Maine, the only U.S. state it could previously be found in.
E. hudsonia is listed as “Threatened” in Michigan.
E. nemorosa is listed as “Threatened” in Michigan.
E. oakesii is “Endangered” in Maine and New Hampshire, the only U.S. states it can be found in.
E. hudsonia is the only eyebright species native to North America that has been evaluated by the IUCN Red List; it is considered to be of “least concern”.

Part of Plant Used/Active Medicinal Compounds:

Eyebright has been used as a tea in folk medicine, in an attempt to treat vision and eye issues (particularly ones that result in discharge from the eyes), coughs, and minor issues or pains in the ears, nose, and head.

Recommendations For Industrial and Home Use:

Cultivating Euphrasia for market sale can be challenging due to the high seedling mortality rate when transplanted, along with the variation in the time it takes a plant to get established, but it is still a feasible option and should definitely be considered. Eyebright plants grow best when paired with a variety of species, but seem to get the most out of legumes, as well as White Clover (Trifolium repens) and Buck’s-Horn Plantain (Plantago coronopus).

Citations

  • Brown, M. R. Franchon, N. et al. (2019, January 08). Life history evolution and phenotypic plasticity in parasitic eyebrights (Euphrasia, Orobanchaceae). doi: https://doi.org/10.1101/362400
    Duke, J. and Foster, S., (1990), A Field Guide to Medicinal Plants and Herbs: Eastern and Central North America, Boston MA, Houghton Mifflin, Page 42.
  • Haines, A. (2011). New England Wild Flower Society’s Flora Novae Angliae: A Manual for the Identification of Native and Naturalized Higher Vascular Plants of New England. Yale University Press.
  • Hellström, K., Rautio, P., Huhta, A.-P., & Tuomi, J. (2004). Tolerance of an annual hemiparasite, Euphrasia stricta agg., to simulated grazing in relation to the host environment. Flora – Morphology, Distribution, Functional Ecology of Plants, 199(3), 247–255. doi:10.1078/0367-2530-00152.
    Integrated Taxonomic Information System. (n.d.). ITIS Standard Report Page: Euphrasia. Retrieved from https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=33588#null
  • Maiz-Tome, L. (2016.) Euphrasia hudsoniana. The IUCN Red List of Threatened Species 2016: e.T64311558A67729491. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T64311558A67729491.en. Downloaded on 28 August 2019.
    USDA. (n.d.). Plants Profile for Eyebright (euphrasia). Results compiled from multiple publications. Retrieved August 29, 2019, from https://plants.usda.gov/core/profile?symbol=EUPHR
  • Wilkins, D. A. (1963). Plasticity and Establishment in Euphrasia. Annals of Botany, 27(3), 533–552. doi:10.1093/oxfordjournals.aob.a083869.

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