Oxalis
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| Oxalis, Wood Sorrel | ||||||||||||
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 Oxalis acetosella | ||||||||||||
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Oxalis is the largest genus in the wood sorrel family Oxalidaceae. Of the approximately 900 known species in the Oxalidaceae, 800 belong to Oxalis. Many of the species are known as Wood Sorrel or Woodsorrel. The genus occurs throughout most of the world, except for the polar areas; species diversity is particularly rich in tropical Brazil and Mexico and in South Africa.
These plants are annual or perennial. The leaves are divided into three to ten or more round, heart-shaped or lanceolate leaflets, arranged in a whorl with all the leaflets of roughly equal size. The majority of species have three leaflets; in these species, the leaves are superficially similar to those of some clovers, though clovers differ in having the leaflets not in a whorl, and of unequal size with two smaller side leaflets and one larger central leaflet. The flowers have five petals, usually fused at the base, and ten stamens; the petal colour varies from white to pink, red or yellow. The fruit is a small capsule containing several seeds. The roots are often tuberous, and several species also reproduce vegetatively by production of bulbils, which detach to produce new plants.
Species
- Oxalis acetosella: Common Wood Sorrel
- Oxalis adenophylla: Sauer Klee Oxalis
- Oxalis albicans: Radishroot Wood Sorrel
- Oxalis albicans subsp. californica: California Wood Sorrel
- Oxalis albicans subsp. pilosa: Radishroot Wood Sorrel
- Oxalis alpina: Mountain Wood Sorrel
- Oxalis articulata: Pink Oxalis
- Oxalis barrelieri: Barrelier's Wood Sorrel
- Oxalis bowiei: Bowie's Sorrel
- Oxalis caerulea: Blue Wood Sorrel
- Oxalis corniculata: Procumbent Yellow Oxalis or Creeping Woodsorrel
- Oxalis debilis: Pink Wood Sorrel
- Oxalis debilis var. corymbosa: Pink Wood Sorrel
- Oxalis decaphylla: Ten-leaved Wood Sorrel or Tenleaf Woodsorrel
- Oxalis dichondrifolia: Peonyleaf Woodsorrel
- Oxalis drummondii: Drummond's Woodsorrel
- Oxalis eggersii: Egger's Woodsorrel
- Oxalis enneaphylla: Scurvy-grass Sorrel
- Oxalis europaea: Upright Yellow Oxalis
- Oxalis frutescens: Shrubby Woodsorrel
- Oxalis frutescens subsp. angustifolia: Shrubby Woodsorrel
- Oxalis grandis: Great Yellow Woodsorrel
- Oxalis hirta: Tropical Woodsorrel
- Oxalis illinoensis: Illinois Woodsorrel
- Oxalis incarnata: Crimson Woodsorrel
- Oxalis intermedia: West Indian Woodsorrel
- Oxalis latifolia: Broadleaf Woodsorrel
- Oxalis macrocarpa: Sorrel
- Oxalis montana: Mountain Woodsorrel
- Oxalis nelsonii: Nelson's Sorrel
- Oxalis oregana: Redwood Sorrel
- Oxalis pes-caprae: Bermuda-buttercup
- Oxalis priceae: Tufted Yellow Woodsorrel
- Oxalis priceae subsp. colorea: Tufted Yellow Woodsorrel
- Oxalis priceae subsp. priceae: Tufted Yellow Woodsorrel
- Oxalis priceae subsp. texana: Texas Woodsorrel
- Oxalis purpurea: Purple Woodsorrel
- Oxalis radicosa: Dwarf Woodsorrel
- Oxalis regnellii: Regnell's Sorrel
- Oxalis regnellii atropurpurea: Purple Shamrock
- Oxalis rosea: Sorrel
- Oxalis rubra: Red Woodsorrel
- Oxalis rugeliana: Coamo
- Oxalis spiralis: Spiral Sorrel
- Oxalis spiralis subsp. vulcanicola: Volcanic Sorrel
- Oxalis stricta: Common Yellow Oxalis
- Oxalis tetraphylla: Fourleaf Sorrel
- Oxalis trilliifolia: Great Oxalis or Threeleaf Woodsorrel
- Oxalis tuberosa: Oca
- Oxalis violacea: Violet Wood Sorrel
Uses
The edible tuberous roots of the Oca (O. tuberosa), somewhat similar to a small potato, have long been cultivated for food in Colombia and elsewhere in the northern Andes mountains of South America. The edible leaves of Scurvy-grass Sorrel (O. enneaphylla) were eaten by sailors in southern South America as a source of vitamin C to avoid scurvy.
A characteristic of many members of this genus is that they contain oxalic acid, giving the leaves and flowers a sour taste, refreshing to chew in small amounts. However, in large amounts, these species are toxic, and interfere with proper digestion. In the past, it was a practice to extract crystals of calcium oxalate for use in treating diseases and as a salt called "sal acetosella", or "sorrel salt" (also known as "salt of lemon").
Several species are grown as ornamental plants in gardens, while others, notably O. pes-caprae and O. corniculata, are pernicious invasive weeds in cultivation away from their native ranges. A species which regularly has leaves with four leaflets, O. tetraphylla, is sometimes misleadingly sold as "four-leaf clover", taking advantage of the mystical status of four-leaf clovers.
External links
- Plant Profile for Oxalis (http://plants.usda.gov/cgi_bin/plant_profile.cgi?symbol=OXALI) — USDA Plant Database
- Glossary of Archaic Chemical Terms: Sorrel (http://webserver.lemoyne.edu/faculty/giunta/archems.html#sorrel)
- Oxalis (http://www.funet.fi/pub/sci/bio/life/plants/magnoliophyta/magnoliophytina/magnoliopsida/oxalidaceae/oxalis/)de:Sauerklee