Practical ecological knowledge for the temperate reader.

Oxalis - Sorrel

Habit: Roots fibrous or woody; bulbs, tubers, or rhizomes often present. Stem: +- 0 or not. Leaf: stipules 0 or small; leaflets 3, generally +- obcordate [not], generally entire, generally green. Flower: petals clawed; styles erect or curved. Fruit: cylindric to spheric, explosively dehiscent. Seed: flat, often ridged; aril translucent.
Species In Genus: 500--950 species: especially temperate. Etymology: (Greek: sour, from acidic taste) Note: Taxonomy difficult, needs study; generally heterostylous; many (especially aliens in California except Oxalis micrantha) ornamental; some noxious weeds; oxalates may be TOXIC to livestock; Oxalis latifolia Kunth possibly naturalized in CCo (Keil 30389, just north of San Simeon), differs from Oxalis purpurea in having flowers in umbel-like cyme; Oxalis hirta L. an historical waif (no recent collections), excluded. [Jepson]

Local Species;

  1. Oxalis acetosella - Common wood sorrel [E-flora] (Only shown in Vancouver Area)
  2. Oxalis corniculata - Yellow oxalis [E-flora]
  3. Oxalis oregana - Redwood sorrel [E-flora][PCBC][TSFTK]
  4. Oxalis stricta - Upright yellow oxalis [E-flora]

Oxalis oregana - Blue Listed [E-flora-3]


The leaves of wood-sorrels (Oxalis spp.) contain oxalic acid, giving them a pleasant, sour taste, but should not be consumed in large quantities".[Turner&Kuhnlein] "In spite of many authors claiming so, oxalates are not a problem for normal healthy humans eating a normally diverse diet." [Kallas EWP]

To reduce page congestion, I will redirect the reader to the forum thread "Oxalates" for a detailed exposition on Oxalic acid, calcium oxalate and Oxalates in general.


Further Investigations;

Several species with edible tuberous roots are cultivated in Mexico and South America. [Nyerges] The larger roots and bulbs of O. tuberosa and O. tetraphylla of South America, and O. deppei of Southern North America and Mexico, have been eaten. [PFAF-5] The American species, Oxalis montana, also has "onion-like tubers which can be eaten either raw or cooked." [WildFoodsForum] It is possible that any species with substantial or plentiful roots could be eaten as a food source. [Personal Note]

Other Uses

Medicinal Uses


O. acetosella: European perennial herb much like Oxalis oregana, this species is established in a few places in shady coniferous woods on the north shore of Burrard Inlet, Greater Vancouver. It is an understorey dominant in the forests of the Capilano River. Probably originating from garden dumpings. (Lomer 91-54 @ UBC)[E-flora-1]

O. acetosella: Carpeting old, undisturbed woodlands in spring, this pretty downy perennial also grows on moss-covered trees and shady walls [WFI]
O. oregana; 2-12"[PSW]
O. corniculata; 1-12"[PSW] Plant maroon to green. [WildPNW] Perennial herb from a slender taproot; stems decumbent to ascending, simple, many, rough hairy, trailing ones freely rooting, herbage brownish to reddish-purple, 5-10 cm tall/long. [IFBC-E-flora2]
O. stricta; Perennial herb from a slender rhizome; stems erect, sometimes prostrate and matted, simple, few to several, smooth or hairy, 10-50 cm tall/long. [IFBC-E-flora4]
Lifecycle Wood sorrels (O. stricta) are annuals but will struggle and survive into perennial-ness in very moderate winter climates. [Kallas EWP]
Flowers Oxalis sp.; White, yellow, red, or pink. 10 stamens, with 5 sepals and 5 petals often united in a spiral twist. The flowers of some species are purplish veined. [Nyerges] Oxalis Sp.; calyx five-lobed; the five petals separate [PWOBC]
O. acetosella: white five-petalled bell-shaped flower (10 - 15 mm) is held solitarily on a stem which comes directly from the roots. [WFI]
O. corniculata; Cluster of 2-7 flowers, deep yellow petals up to 1/4 in. [WildPNW]
O. oregana; solitary pink upright funnel-like flowers. [PSW]
O. stricta; "peduncles up to 7 -flowered; petals 4-9 mm. long, yellow" [HNW]
Fruits Oxalis sp.; A narrow, linear, five-celled pod. [Nyerges]
O. corniculata;capsules oblong, 6-25 mm.long, pubescent. [HNW]'
Leaves Oxalis sp.; Trifoliate (three leaflets), each leaflet heart shaped with a midrib or midfold. Leaflets unfold in sunshine and retract during cloudy weather and at night.[Nyerges] "[leaflets] at the tip of the petiole." [PWOBC] leaves basal and alternate [HNW]
Stem "The green flower stems are stout and succulent". Conspicuous long stems (up to about eight inches tall) [Nyerges]
O. corniculata; Slender creeping stems rooting at nodes. [PSW]'
O. stricta; "stems prostrate to erect."[HNW]
Root Oxalis Sp.; fleshy underground rhizomes [PWOBC]
O. corniculata; Deep fleshy taproot.[WildPNW]

O. corniculata: Mesic fields and waste places in the lowland zone; frequent on S Vancouver Island, the Gulf Islands and adjacent coast; introduced from Eurasia. [IFBC-E-flora-2]
O. oregana: Moist forests in the lowland zone; rare on the Queen Charlotte Islands and W coast of Vancouver Island; S to CA. Native [IFBC-E-flora-3]
O. stricta: Moist disturbed areas and ditches in the lowland zone; rare in the lower Fraser Valley; introduced from the U.S. [E-flora-4]

O. acetosella: Exotic [E-flora-1]
O. corniculata Exotic [E-flora-2]
O. oregana Native [E-flora-3]
O. stricta Exotic [E-flora-4]

Similar Species Wood sorrel leaflets are heart-shaped; and clover are typically not heart-shaped, but "...tend to be round, egg-shaped, or oblong." [Kallas EWP] Nardoo (Marsilea drummondii), a native of Australia, also toxic and also edible, looks like Oxalis but has 4 leaves. It most certainly doesn't grow in the Pacific Northwest of North America and, from what I've read, only grows in Australia and Tasmania. The difference between Sorrel and the species I mentioned is clear with a simple taste test. Sorrel is lemon-sour from it's oxalic acid content.[Personal Note]


Medicinal Uses
Wood Sorrel (Oxalis acetosella) - Throughout Europe [PDR]

O. corniculata; It is used in the treatment of influenza, fever, urinary tract infections, enteritis, diarrhoea, traumatic injuries, sprains and poisonous snake bites[147]. [PFAF-3]


O. corniculata; Per 100g (fresh weight), crude fiber 0.9g, 86g water. [Turner&Kuhnlein] 6050µg beta carotene.[173][PFAF-3]




Drummond's Woodsorrel (Oxalis drummondii) Decoction of bulb is analgesic. Poultice of bulbs, alone or in compound, applied to sores.[NAEth Moerman]

Wood Sorrel (Oxalis montana): All parts can be eaten. The whole plant used as a lemon flavoring[WildFoodForum] whole plant boiled to yield a yellow dye. [NAEth Moerman]

Violet Woodsorrel (Oxalis violacea)


1st search completed. Needs new journal artices. Sources. Is nutritional table from Turner/Kuhnlein????

Page last modified on Sunday, February 13, 2022 12:39 PM