Oxalis acetosella (wood sorrel or common wood sorrel) is a rhizomatous plant from the genus Oxalis, common in most of Europe and parts of Asia. The binomial name is Oxalis acetosella, because of 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 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 and Pentecost, when the Psalms which end with Hallelujah were sung.