''Oxalis acetosella'', the wood sorrel or common wood sorrel, is a rhizomatous

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the family ''

Oxalidaceae The Oxalidaceae, or wood sorrel family, are a small family of five genera of herbaceous plants, shrubs and small trees, with the great majority of the 570 species in the genus ''Oxalis'' (wood sorrels). Members of this family typically have divid ...

'', common in most of

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and parts of

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''acetosella'' refers to its sour taste. The common name wood sorrel is often used for other plants in the genus ''Oxalis''. In much of its range it is the only member of its

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

and hence simply known as "the" wood sorrel. While common wood sorrel may be used to differentiate it from most other species of ''Oxalis'', in North America, '' Oxalis montana'' is also called common wood sorrel. It is also known as ''Alleluia'' because it blossoms between

Easter Easter,Traditional names for the feast in English are "Easter Day", as in the '' Book of Common Prayer''; "Easter Sunday", used by James Ussher''The Whole Works of the Most Rev. James Ussher, Volume 4'') and Samuel Pepys''The Diary of Samuel ...

and

Pentecost Pentecost (also called Whit Sunday, Whitsunday or Whitsun) is a Christianity, Christian holiday which takes place on the 50th day (the seventh Sunday) after Easter Sunday. It commemorates the descent of the Holy Spirit upon the Apostles in the Ne ...

, when the

Psalms The Book of Psalms ( or ; he, תְּהִלִּים, , lit. "praises"), also known as the Psalms, or the Psalter, is the first book of the ("Writings"), the third section of the Tanakh, and a book of the Old Testament. The title is derived ...

which end with

Hallelujah ''Hallelujah'' ( ; he, ''haləlū-Yāh'', meaning "praise Yah") is an interjection used as an expression of gratitude to God. The term is used 24 times in the Hebrew Bible (in the book of Psalms), twice in deuterocanonical books, and four tim ...

are sung.

Description

The plant has trifoliate compound

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

, the leaflets heart-shaped and folded through the middle, that occur in groups of three on petioles up to long. It flowers from spring to midsummer with small white open-faced

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s with pink venation. Reddish or mauve flowers also occur rarely.Clapham, A.R., Tutin, T.G. and Warburg E.F. 1968. ''Excursion Flora of the British Isles''. Cambridge University Press. During the night or when it rains the flowers close and the leaves fold. As with other species of wood sorrel, the leaves are sometimes eaten by humans. An oxalate called "sal acetosella" was formerly extracted from the plant by boiling it. '' Anemonoides nemorosa'' (wood anemone) is similar. Both have white flowers, are small, and are found in woody shady places. ''Anemonoides nemorosa'' however has palmately lobed leaves and does not have true petals but large sepals which are petal-like.Parnell, J. and Curtis, T. 2012. ''Webb's An Irish Flora.'' Cork University Press.

Habitat

It grows in woods and shady places in the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

Distribution

The plant is commonly found in Great Britain and Ireland.Scannell, M.J.P. and Synnott, D.M. 1972 ''Census Catalogue of the Flora of Ireland'' Dublin Paperback. Stationery Office. ASIN: B0006CRR94 pp 127

Note

The common wood sorrel is sometimes referred to as a

shamrock A shamrock is a young sprig, used as a symbol of Ireland. Saint Patrick, Ireland's patron saint, is said to have used it as a metaphor for the Christian Holy Trinity. The name ''shamrock'' comes from Irish (), which is the diminutive of ...

and given as a gift on Saint Patrick's Day. This is due to its trifoliate

clover Clover or trefoil are common names for plants of the genus ''Trifolium'' (from Latin ''tres'' 'three' + ''folium'' 'leaf'), consisting of about 300 species of flowering plants in the legume or pea family Fabaceae originating in Europe. The genus ...

-like leaf, and to early references to shamrock being eaten. Despite this, it is generally accepted that the plant described as "true" shamrock is a species of

, usually lesser clover ('' Trifolium dubium'').

References

External links

Giftpflanzen.com — Waldsauerklee

oxalis-acetosella.com — ''Oxalis acetosella''
{{Taxonbar, from=Q158576 acetosella Flora of Asia Flora of Europe Hardwood forest plants Plants described in 1753 Taxa named by Carl Linnaeus Medicinal plants Garden plants of Asia Garden plants of Europe Groundcovers