Euphrasia

Euphrasia, or eyebright, is a genus of about 450 species of herbaceous flowering plants in the family Orobanchaceae (formerly included in the Scrophulariaceae), with a cosmopolitan distribution. They are hemiparasitic on grasses and other plants. The common name refers to the plant's use in treating eye infections.
Many species are found in alpine or sub-alpine meadows where snow is common. Flowers usually are borne terminally, are zygomorphic, and have a lower petal shaped like a lip. The most common flower colours are purple, blue-white, and violet. Some species have yellow markings on the lower petal to act as a guide to pollinating insects.
Alternative names, mainly in herbalism, are Augentrostkraut, Euphrasiae herba, Herba Euphrasiae and Herbe d'Euphraise.
Use in herbalism and medicine
The plant was known to classical herbalists, but then was not referred to until mentioned again in 1305. Nicholas Culpeper assigned it to the Zodiac sign Leo, claiming that it strengthened the brain. It was also used to treat bad memory and vertigo.
In the Elizabethan era, the plant was used in ales, and Gervase Markham's Countrie Farm (1616) said that one should "Drinke everie morning a small draught of Eyebright wine."
Herbalists use eyebright as a poultice with or without concurrent administration of a tea for the redness, swelling, and visual disturbances caused by blepharitis, and conjunctivitis. The herb is also used for eyestrain and to relieve inflammation caused by colds, coughs, sinus infections, sore throats, and hay fever.
Parts used include the leaf, the stem, and small pieces of the flowers. Typical preparations include a warm compress, or tea. Eyebright preparations are also available as an extract or capsule.
A 2010 report from the European Medicines Agency on the efficacy of Euphrasia remedies states:
From the presence of secondary metabolites, an astringent and anti-inflammatory activity can be hypothesized for Euphrasia preparations. The ocular use of Euphrasia is based upon tradition. However, since the efficacy of the claimed ocular uses is undocumented and external eye application is not hygienic, therapeutic use cannot be recommended.
Phylogeny
The phylogeny of the genera of Rhinantheae has been explored using molecular characters. Euphrasia belongs to the core Rhinantheae. Euphrasia is the sister genus to Odontites, Bellardia, Tozzia, and Hedbergia. In turn, these five genera share phylogenetic affinities with Bartsia.
Taxonomy and identification
The genus Euphrasia is taxonomically complicated due to many species being interfertile and prone to hybridisation. Despite there having been a number of taxonomic revisions the appropriate rank of many taxa, as well as the relationships between them, remains unclear.
Selected species
Euphrasia × aequalis
Euphrasia alpina
Euphrasia alsa F.Muell.
Euphrasia anglica Pugsley
Euphrasia arctica Lange ex Rostrup
Euphrasia arctica subsp. arctica (E.borealis auct. non (F.Towns.) Wettsd.)
Euphrasia arctica sybsp. borealis (F.Towns) Yeo
Euphrasia arguta – believed extinct, rediscovered 2008
Euphrasia azorica
Euphrasia brevipila
Euphrasia calida
Euphrasia cambrica Pugsley
Euphrasia campbelliae Pugsley
Euphrasia collina R.Br. – purple eyebright
Euphrasia collina ssp. muelleri – Mueller's eyebright
Euphrasia collina ssp. osbornii – Osborn's eyebright
Euphrasia confusa Pugsley
Euphrasia coreana W.Becker – Korean eyebright
Euphrasia cuneata – North Island eyebright
Euphrasia crassiuscula Gand
Euphrasia fabula
Euphrasia fennica
Euphrasia foulaensis F.Towns. ex Wettst
Euphrasia fragosa – shy eyebright, Southport eyebright
Euphrasia frigida Pugsley – cold-weather eyebright
Euphrasia gibbsiae
Euphrasia gibbsiae subsp. psilantherea
Euphrasia glabrescens
Euprasia grandiflora
Euphrasia heslop-harrisonii Pugsley
Euphrasia hirtella
Euphrasia hudsoniana – Hudson's eyebright
Euphrasia insignis Wettst
Euphrasia kingii
Euphrasia lasianthera – hairy eyebright
Euphrasia marshallii Pugsley
Euphrasia micrantha Rchb.
Euphrasia minima
Euphrasia nemorosa (Pers.) Wallr. – common eyebright
Euphrasia officinalis coll. – doctor's eyebright, or medical eyebright
Euphrasia officinalis L – see Euphrasia rostkoviana
Euphrasia oakesii – Oakes' eyebright
Euphrasia ostenfeldii (Pugsley) Yeo
Euphrasia parviflora
Euphrasia pseudokerneri Pugsley – chalk eyebright
Euphrasia randii – small eyebright
Euphrasia rivularis Pugsley
Euphrasia rostkoviana Hayne – red eyebright, "figwort"
Euphrasia rostkoviana subsp. rostkoviana
Euphrasia rostkoviana subsp. montana (Jord.) Wettst.
Euphrasia rotundifolia Pugsley
Euphrasia ruptura – extinct
Euphrasia salisburgensis Funk.
Euphrasia scabra R.Br. – rough eyebright
Euphrasia scottica Wettst.
Euphrasia semipicta – peninsula eyebright
Euphrasia striata R.Br.
Euphrasia stricta D.Wolff ex J.F.Lehm.
Euphrasia subarctica – arctic eyebright
Euphrasia suborbicularis – roundleaf eyebright
Euphrasia tatrae
Euphrasia tetraquetra (Bréb.) .
Euphrasia vernalis
Euphrasia × vestita
Euphrasia vigursii Davey
Euphrasia × villosa
Euphrasia vinacea – glacier eyebright
Euphrasia zelandica
Euphrasia sp. 'Bivouac Bay' – Bivouac Bay eyebright
Footnotes
References
Orobanchaceae genera
Taxa named by Carl Linnaeus
Parasitic plants