Habitat :The Eyebright is the only British species of a genus containing twenty species distributed over Europe, Northern and Western Asia and North America.
Common Name :Eyebright
Alternative names, mainly in herbalism, are Augentrostkraut, Euphrasiae herba, Herba Euphrasiae and Herbe d’Euphraise.
It is an elegant little plant, 2 to 8 inches high, an annual, common on heaths and other dry pastures, especially on a chalky soil, and flowering from July to September, with deeply-cut leaves and numerous, small, white or purplish flowers variegated with yellow.
It varies much in size and in the colour of the corolla, which changes to quite white and yellow. On the mountains and near the sea, or in poor soil, it is often a tiny plant, only an inch or so high, with the stem scarcely branched, but in rich soil it assumes the habit of a minute shrub and forms a spreading tuft, 8 or 9 inches high. The leaves, also, are sometimes almost round, and at other times pointed and narrow, their margins, however, always deeply cut into teeth. The variability of the Eyebright has led to much discussion as to how many species of it are known: continental botanists define numerous species, but our botanists follow Bentham and Hooker, who considered that there is only one very variable species, with three principal varieties: officinalis proper, in which the corolla lip equals or exceeds the tube and the bracts of the flower-spike are broad at the base; gracilis, more slender, the corolla lip shorter than the tube, and the flower-spike bracts narrowed at the base, and maritima, found on the shores of the Shetland Islands in which the capsule is much longer than the calyx.
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The stem is erect and wiry, either unbranched in small specimens, or with many opposite branches. The leaves are 1/6 to 1/2 inch long and about 1/4 inch broad, opposite to one another on the lower portion of the stem, alternate above, more often lance-shaped, though sometimes, as already stated, much broader, and with four to five teeth on each side.
The flowers, white, or lilac and purpleveined, are in terminal spikes, with leafy bracts interspersed. The structure of the flower places the plant in the family of the Foxglove and the Speedwell – Scrophulariaceae. The corolla is two-lipped, its lower, tube-like portion being enclosed in a green calyx, tipped with four teeth. The upper lip is two-lobed and arches over the stamens, forming a shelter from the rain. The lower lip is spreading and three-lobed, each lobe being notched. A yellow patch emphasizes the central lobe and purple ‘honey guides’ on both upper and lower lips – marked streaks of colour – point the way down the throat. Four stamens, with brown, downy anthers lie under the upper lip, in pairs, one behind the other; on the underside of each anther is a stiff spur, the two lowest spurs longer than the others and projecting over the throat of the flower. The upper spurs end in miniature brushes which are intended to prevent the pollen being scattered at the side and wasted. When a bee visitor comes in search of the honey lying round the ovary at the bottom of the petal tube, it knocks against the projecting anther spurs, which sets free the pollen, so that it falls on the insect’s head. On visiting the next flower, the bee will then rub its dusty head against the outstanding stigma which terminates the style, or long thread placed on the ovary and projects beyond the stamens, and thus cross-fertilization is effected. But though this is the normal arrangement, other and smaller flowers are sometimes found, which suggests that self- fertilization is aimed at. In these, the corolla elongates after opening, and as the stamens are attached to it, their heads are gradually brought almost up to the stigma and eventually their pollen will fertilize it.
The seeds in all kinds of the flowers are produced in tiny, flattened capsules, and are numerous and ribbed.
The Eyebright will not grow readily in a garden if transplanted, unless ‘protected’ apparently, by grass. The reason for this is that it is a semi-parasite, relying for part of its nourishment on the roots of other plants. Above ground, it appears to be a perfectly normal plant, with normal flowers and bright green leaves – the leaves of fully parasitic plants are almost devoid of green colouring matter – but below the surface, suckers from its roots spread round and lie on the rootlets of the grassplants among which it grows. Where they are in contact, tiny nodules form and send absorption cells into the grass rootlets. The grass preyed upon does not, however, suffer very much, as the cells penetrate but a slight distance, moreover the Eyebright being an annual, renewing itself from year to year, the suckers on the grass roots to which it is attached also wither in the autumn, so there is no permanent drain of strength from the grass.
Part Used: Herb.(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.)
Constituents: The precise chemical constituents of the herb have not yet been recorded; it is known to contain a peculiar tannin, termed Euphrasia-Tannin acid (which gives a dark-green precipitate with ferric salts and is only obtainable by combination with lead) and also Mannite and Glucose, but the volatile oil and acrid and bitter principle have not yet been chemically analyzed.
Uses: Although neglected nowadays by the faculty, modern herbalists still retain faith in this herb and recommend its use in diseases of the sight, weakness of the eyes, ophthalmia, etc., combining it often with Golden Seal in a lotion stated to be excellent for general disorders of the eyes. The juice obtained by expression from the plant in the fresh state is sometimes employed, or an infusion in milk, but the simple infusion in water is the more usual form in which it is applied. An infusion of 1 OZ. of the herb to a pint of boiling water should be used and the eyes bathed three or four times a day. When there is much pain, it is considered desirable to use a warm infusion rather more frequently for inflamed eyes till the pain is removed. In ordinary cases, the cold application is found sufficient.It was also used to treat bad memory and vertigo.
In Iceland, the expressed juice is used for most ailments of the eye, and in Scotland the Highlanders make an infusion of the herb in milk and anoint weak or inflamed eyes with a feather dipped in it.
The dried herb is an ingredient in British Herbal Tobacco, which is smoked most usefully for chronic bronchial colds.
Homoeopathists hold that Eyebright belongs to the order of scrofula-curing plants, and Dr. Fernie tells us that it has recently been found by experiment:
‘to possess a distinct sphere of curative operation, within which it manifests virtues which are as unvarying as they are potential. It acts specifically on the mucous lining of the eyes and nose and the upper part of the throat to the top of the windpipe, causing when given so largely as to be injurious, a profuse secretion from these parts; if given of reduced strength, it cures the troublesome symptoms due to catarrh. Hay Fever, and acute attacks of cold in the head may be checked by an immediate dose of the infusion repeated every two hours. A medicinal tincture is prepared from the whole plant with spirits of wine, of which a lotion is made with rose-water, for simple inflammation of the eyes. Thirty drops of the tincture should be mixed with a wineglassful of rose-water for making this lotion, which may be used several times a day.’ click to see :
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.
The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplements, it is always advisable to consult with your own health care provider.