This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
Seeds have been found in late Glacial beds at Edinburgh, and in Neolithic beds there and in Essex. The North and Arctic Temperate Zones describe its limit, the plant occurring in Arctic Europe, North Africa, N. and W. Asia to the Himalayas, and N. America. It is found in most parts of Great Britain, but not in Hunts, Cardigan, South Lincs, Mid Lancs, Shetlands, elsewhere as far north as the Orkneys. It ascends to nearly 4000 ft. in the Highlands. It is found in Ireland and in the Channel Islands.
Woods, where there is little or no undergrowth to outgrow this tender little wild flower, are the places in which to look for Wood Sorrel. It is a shade-loving plant which may be found growing on the sloping banks of little tree-sheltered ravines removed from woods, but is most luxuriant and widespread in the latter.
This delicate, pretty, bulbous plant has no aerial stem. The leaves are ternate or divided into 3, and consist of 3 leaflets, hairy, stalked, three-nerved, the leaf-stalks not winged. The root is toothed and creeping.
The scape or flowering stem is longer than the leaves, with two bracts or leaflike organs at the top, and is single-flowered. The flowers are white with purple veins, and of two kinds, the smaller being cleistogamic, like the Violet. When flowering is over the scape or flowering stem bends down, and when the seed is ripe it becomes erect. When ripe the fruits may be opened at the angles, and the seeds are thrown to a distance. The capsule is divided into five chambers, with two black, smooth seeds in each attached to the central pillar.
Three inches is the greatest height of this lowly, graceful flower, which blooms in April and May. It is perennial, increasing by offsets.
Wood Sorrel is dimorphic, i.e. there are two or more forms, and the flowers are cleistogamic, like those of the Violet. Here the smaller ones are cleistogamic and bury the capsules in the ground, and the larger ones are normal and conspicuous. The anthers and stigma mature together. In the rain the flowers bend over. There are five fleshy nectaries or knobs at the base of the petals. The flowers open between 9 a.m. and 6 p.m. The dimorphic characteristics, with the variations between long- and short-styled forms, affords greater chance of cross-pollination.
Wood Sorrel disperses its seeds immediately around it. When the capsule is mature it is stretched, and this causes it to split open and eject the seeds, by a catapult motion, to some distance. Really the seeds eject themselves. The cells of the inner layer are small and swollen. The coat splits down one side, and the inner cells expand, turn the coat inside out, the inner and outer coat changing place.
This plant is a lover of humus, and requires a humus soil, being also to a certain extent a clay-lover, requiring a clayey soil.
The Wood Sorrel is infested by no fungi or insect pests.
Oxalis, Pliny, is derived from the Greek oxus, sharp, acid, and aceto-sella is from Latin acetum, sour wine, vinegar; Sorrel is derived from sour.
Wood Sorrel is known by many names: Alleluia, Allolida, Bird's Bread-and-Cheese, Bread-and-Cheese, Bird's Clover, Sorrell, Cuckoo's, Gowk's, or Sour Clover, Cuckoo's Bread-and-cheese, Cuckoo-flower, Cuckoo-spice, Cuckoo's Victuals, Sour Grass, Green Sauce, God A'mighty's Bread and Cheese, Gowk Meat, Hallelujah, Hare's Meat, Hearts, Lady's Cakes, Lady's Clover, Lady's Meat, Laverocks, Lu-jula, Rabbit Meat, Shamrock, Sheep Sorrel, Sleeping" Beauty, Sleeping Clover, French or Wood Sorrel, Sour Clover, Sour Sals, Stabwort, Stob-wort, Stopwort, Stub-wort, Wood-sour, Wood-sower.
Wood Sorrel was called Stabwort because it was said to be good for wounds, punctures, stabs, etc, and Stub-wort, from growing at the roots of old trees. The name Alleluia is explained, "By reason when it springeth forth and flowereth Alleluia was wont to be sung in churches " (i.e. between Easter and Pentecost).
The name Hearts is from the shape of the leaves.
The flowers were formerly called fairy bells, and it was thought that the fairies were summoned to their moonlight revels by these bells. Wood Sorrel was called St. Cecilia's Flower, St. Cecilia's Day being celebrated 22nd November, on account of the trumpet-like form of the leaves. Another legend attributes the spotting of the leaves to their being blood-drops from the Cross.
The foliage is extremely sharp and acid, hence some of its names. It contains a binoxalate of potash. The juice is expressed and evaporates, and the crystals are produced from which we obtain salts of lemon. This is used for removing ink stains. It is poisonous and must be used with caution. Wood Sorrel was used as a salad. It has been endowed with cooling, antiscorbutic (remedy for skin diseases), and diuretic properties. An infusion was given in cases of fever.
Photo. J. H. Crabtree - Wood Sorrel (oxalis Acetosella, L.)
The leaves expand in wet weather and droop in dry weather, and are sensitive also to the touch. They change their position in relation to the light in four ways: the whole leaf may move, it may change its angle, the chlorophyll granules in the cells may rearrange themselves, as in Duckweed, or the grains may alter their form. The leaves close and droop in the sun and at night. The short stalks effect these two movements, absorption and transpiration enabling this sensitiveness to show itself in action.
Essential Specific Characters: 70. Oxalis Acetosella, L. - Stem a rhizome, rhizome toothed, leaves ternate, hairy, radical, leaflets obcordate, peduncles 1-flowered, flower white with purple veins, 2 bracts in middle of scape.