Euphrasia officinalisL.

eyebright

WFO wfo-0000682538 Accepted WFO 2026-06 8 photographs CC0 / CC BY

Plate 1 figs. a–h · 8 separate observations

Euphrasia officinalis, photographed by María Regina Silva
fig. a María Regina Silva, CC BY 4.0 / 2022-02-26 / obs. 181196693

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 30 botanical countries

Regions where Euphrasia officinalis is native: Transcaucasus, Türkiye, West Siberia, Albania, Austria, Baltic States, Belarus, Belgium, Bulgaria, Central European Russia, Czechia-Slovakia, Denmark, East European Russia, Finland, France, Germany, Great Britain, Greece, Hungary, Ireland, Italy, Netherlands, North European Russia, Northwest European Russia, NW. Balkan Pen., Poland, Romania, Sweden, Switzerland, Ukraine TranscaucasusTürkiyeWest SiberiaAlbaniaAustriaBaltic StatesBelarusBelgiumBulgariaCentral European RussiaCzechia-SlovakiaDenmarkEast European RussiaFinlandFranceGermanyGreeceHungaryIrelandItalyNetherlandsNorth European RussiaNorthwest European RussiaNW. Balkan Pen.PolandRomaniaSwedenSwitzerlandUkraine
Native distribution of Euphrasia officinalis, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows.
RegionTDWG codeContinent
Albania ALB EUROPE
Austria AUT
Baltic States BLT
Belarus BLR
Belgium BGM
Bulgaria BUL
Central European Russia RUC
Czechia-Slovakia CZE
Denmark DEN
East European Russia RUE
Finland FIN
France FRA
Germany GER
Great Britain GRB
Greece GRC
Hungary HUN
Ireland IRE
Italy ITA
Netherlands NET
North European Russia RUN
Northwest European Russia RUW
NW. Balkan Pen. YUG
Poland POL
Romania ROM
Sweden SWE
Switzerland SWI
Ukraine UKR
Transcaucasus TCS ASIA-TEMPERATE
Türkiye TUR
West Siberia WSB

Not drawn on the map: Great Britain. We hold no public-domain boundary for this region, so it is listed rather than guessed at.

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Flowering 168 in flower of 168 examined

Proportion of examined Euphrasia officinalis in flower, by month
Month In flower Examined Share 95% interval
Jan 8 8 100% 68% to 100%
Feb 14 14 100% 78% to 100%
Mar 10 10 100% 72% to 100%
Apr 6 6 100% 61% to 100%
May 1 1 too few examined
Jun 6 6 100% 61% to 100%
Jul 29 29 100% 88% to 100%
Aug 56 56 100% 94% to 100%
Sep 33 33 100% 90% to 100%
Oct 3 3 too few examined
Nov 1 1 too few examined
Dec 1 1 too few examined

Peak flowering in Jan. Each bar is the share of Euphrasia officinalis observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 168 of 168 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 4 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Where it actually grows measured, from 885 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low -15.2 °C -7.2 °C 1.6 °C
Warmest month, mean daily high 12.6 °C 18.3 °C 23.1 °C
Annual rainfall 731 mm 1,339 mm 2,354 mm
Rainfall in the driest quarter 121 mm 222 mm 435 mm

It is found where winters are severely cold. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 885 research-grade observations of Euphrasia officinalis that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 90 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Bartsia imbricata Lapeyr.
  • Euphrasia agrestis Arrond.
  • Euphrasia anglica Pugsley
  • Euphrasia campestris Jord.
  • Euphrasia cantalensis (Chabert) Chabert
  • Euphrasia capitulata F.Towns.
  • Euphrasia carniolica A.Kern.
  • Euphrasia cebennensis B.-A.Martin
  • Euphrasia cuspidata St.-Lag.
  • Euphrasia cuspidatissima St.-Lag.
  • Euphrasia danica T.Gliem.
  • Euphrasia exigua Reut.
  • Euphrasia fennica Kihlm.
  • Euphrasia fennica f. brevidens (H.Lindb. ex Cajander) Hagfors
  • Euphrasia fennica subsp. aestivalis Ganesch.
  • Euphrasia hirtella f. macrantha H.Lindb.
  • Euphrasia hirtella var. fennica (Kihlm.) H.Lindb.
  • Euphrasia imbricata Pers.
  • Euphrasia jordaniana Sennen
  • Euphrasia lapeyrousei Soy.-Will.
  • Euphrasia lapeyrousii Soy.-Will.
  • Euphrasia maculata Gilib.
  • Euphrasia minor Link
  • Euphrasia mollis Ledeb. ex Benth.

and 66 more.

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. USDA PLANTS Database. common name, checklist symbol EURO10. public domain. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.