FNA: Oxalis oregana vs. Oxalis caerulea

	Oxalis oregana	Oxalis caerulea
	Oregon oxalis, Oregon wood-sorrel, red wood-sorrel	blue wood-sorrel
Habit	Herbs perennial, acaulous, rhizomes present, fleshy-thickened, densely scaly, stolons absent, bulbs absent.	Herbs perennial, acaulous, rhizomes and stolons absent, bulb solitary; bulb scales (3–)5–7-nerved.
Leaves	basal, clustered at rhizome tips; petiole 5–15(–21) cm, sparsely to densely villous, hairs rusty; leaflets 3, green, broadly obcordate, 10–30(–40) mm, lobed 1/5–1/4 length, lobes apically convex, surfaces sparsely villous, oxalate deposits absent.	basal; petiole 3–10(–13) cm; leaflets (3–)4(–5), green to purplish abaxially, green adaxially, obtriangular to obcordate, 5–22 mm, lobed 1/5–1/2 length, lobes apically rounded, surfaces glabrous, oxalate deposits absent or as few punctate tubercles near lobe apices.
Inflorescences	1-flowered; scapes (6–)11–25 cm, glabrous or sparsely villous.	umbelliform cymes, (1–)2–7-flowered; scapes 6–12(–15) cm, glabrous.
Flowers	heterostylous; sepal apices without tubercles; petals white to deep pink, usually with yellow spot sub-basally and prominent purple veins, (8–)15–25 mm.	distylous; sepal apices with 2 orange, linear tubercles; petals red to pinkish lavender, 8–10 mm.
Capsules	ovoid, 6–8(–12) mm, glabrate.	ellipsoid, 3.5–6 mm, glabrous.

	Oxalis oregana	Oxalis caerulea
Phenology	Flowering Feb–Sep.	Flowering Jun–Sep.
Habitat	Douglas fir, mixed fir, cedar-spruce, mixed conifer, and hemlock-maple forests, maple woodlands, alder glens, Gaultheria thickets, stream banks.	Streambeds, stream banks, meadows, pinyon-juniper, pine-oak-juniper, or pine-aspen woodlands.
Elevation	10–800(–1000) m. (0–2600(–3300) ft.)	(1800–)2000–2600 m. ((5900–)6600–8500 ft.)
Distribution	CA; OR; WA; BC [WildflowerSearch map] [BONAP county map]	AZ; CO; NM; Mexico (Chihuahua, Durango, Sonora) [BONAP county map]
Discussion	Oxalis oregana has sometimes been treated as a disjunct geographical taxon of the European O. acetosella Linnaeus (see comments under 21. O. montana). (Discussion copyrighted by Flora of North America; reprinted with permission.)
Source	FNA vol. 12, p. 148.	FNA vol. 12, p. 148.
Parent taxa	Oxalidaceae > Oxalis	Oxalidaceae > Oxalis
Sibling taxa	O. albicans, O. articulata, O. bowiei, O. brasiliensis, O. caerulea, O. californica, O. colorea, O. corniculata, O. debilis, O. decaphylla, O. dichondrifolia, O. dillenii, O. drummondii, O. florida, O. frutescens, O. grandis, O. hirta, O. hispidula, O. illinoensis, O. incarnata, O. intermedia, O. latifolia, O. laxa, O. macrantha, O. metcalfei, O. montana, O. pes-caprae, O. pilosa, O. purpurea, O. stricta, O. suksdorfii, O. texana, O. triangularis, O. trilliifolia, O. violacea	O. albicans, O. articulata, O. bowiei, O. brasiliensis, O. californica, O. colorea, O. corniculata, O. debilis, O. decaphylla, O. dichondrifolia, O. dillenii, O. drummondii, O. florida, O. frutescens, O. grandis, O. hirta, O. hispidula, O. illinoensis, O. incarnata, O. intermedia, O. latifolia, O. laxa, O. macrantha, O. metcalfei, O. montana, O. oregana, O. pes-caprae, O. pilosa, O. purpurea, O. stricta, O. suksdorfii, O. texana, O. triangularis, O. trilliifolia, O. violacea
Synonyms	O. acetosella subsp. oregana, O. oregana var. smalliana, O. oregana var. tracyi, O. smalliana	Ionoxalis caerulea
Name authority	Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 211. (1838)	(Small) R. Knuth: Notizbl. Bot. Gart. Berlin-Dahlem 7: 316. (1919)
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Oxalis caerulea

Oregon oxalis, Oregon wood-sorrel, red wood-sorrel

blue wood-sorrel

Habit

Herbs perennial, acaulous, rhizomes present, fleshy-thickened, densely scaly, stolons absent, bulbs absent.

Herbs perennial, acaulous, rhizomes and stolons absent, bulb solitary; bulb scales (3–)5–7-nerved.

Leaves

basal, clustered at rhizome tips;

petiole 5–15(–21) cm, sparsely to densely villous, hairs rusty;

leaflets 3, green, broadly obcordate, 10–30(–40) mm, lobed 1/5–1/4 length, lobes apically convex, surfaces sparsely villous, oxalate deposits absent.

basal;

petiole 3–10(–13) cm;

leaflets (3–)4(–5), green to purplish abaxially, green adaxially, obtriangular to obcordate, 5–22 mm, lobed 1/5–1/2 length, lobes apically rounded, surfaces glabrous, oxalate deposits absent or as few punctate tubercles near lobe apices.

Inflorescences

1-flowered;

scapes (6–)11–25 cm, glabrous or sparsely villous.

umbelliform cymes, (1–)2–7-flowered;

scapes 6–12(–15) cm, glabrous.

Flowers

heterostylous;

sepal apices without tubercles;

petals white to deep pink, usually with yellow spot sub-basally and prominent purple veins, (8–)15–25 mm.

distylous;

sepal apices with 2 orange, linear tubercles;

petals red to pinkish lavender, 8–10 mm.

Capsules

ovoid, 6–8(–12) mm, glabrate.

ellipsoid, 3.5–6 mm, glabrous.

Oxalis oregana

Oxalis caerulea

Phenology

Flowering Feb–Sep.

Flowering Jun–Sep.

Habitat

Douglas fir, mixed fir, cedar-spruce, mixed conifer, and hemlock-maple forests, maple woodlands, alder glens, Gaultheria thickets, stream banks.

Streambeds, stream banks, meadows, pinyon-juniper, pine-oak-juniper, or pine-aspen woodlands.

Elevation

10–800(–1000) m. (0–2600(–3300) ft.)

(1800–)2000–2600 m. ((5900–)6600–8500 ft.)

Distribution

CA; OR; WA; BC

[WildflowerSearch map]

[BONAP county map]

AZ; CO; NM; Mexico (Chihuahua, Durango, Sonora)

[BONAP county map]

Discussion

Oxalis oregana has sometimes been treated as a disjunct geographical taxon of the European O. acetosella Linnaeus (see comments under 21. O. montana).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source

FNA vol. 12, p. 148.

Parent taxa

Oxalidaceae > Oxalis

Sibling taxa

O. albicans, O. articulata, O. bowiei, O. brasiliensis, O. caerulea, O. californica, O. colorea, O. corniculata, O. debilis, O. decaphylla, O. dichondrifolia, O. dillenii, O. drummondii, O. florida, O. frutescens, O. grandis, O. hirta, O. hispidula, O. illinoensis, O. incarnata, O. intermedia, O. latifolia, O. laxa, O. macrantha, O. metcalfei, O. montana, O. pes-caprae, O. pilosa, O. purpurea, O. stricta, O. suksdorfii, O. texana, O. triangularis, O. trilliifolia, O. violacea

O. albicans, O. articulata, O. bowiei, O. brasiliensis, O. californica, O. colorea, O. corniculata, O. debilis, O. decaphylla, O. dichondrifolia, O. dillenii, O. drummondii, O. florida, O. frutescens, O. grandis, O. hirta, O. hispidula, O. illinoensis, O. incarnata, O. intermedia, O. latifolia, O. laxa, O. macrantha, O. metcalfei, O. montana, O. oregana, O. pes-caprae, O. pilosa, O. purpurea, O. stricta, O. suksdorfii, O. texana, O. triangularis, O. trilliifolia, O. violacea

Synonyms

O. acetosella subsp. oregana, O. oregana var. smalliana, O. oregana var. tracyi, O. smalliana

Ionoxalis caerulea

Name authority

Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 211. (1838)

(Small) R. Knuth: Notizbl. Bot. Gart. Berlin-Dahlem 7: 316. (1919)

Web links

Local floras: BC, CA, OR, WA
Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog.
WildflowerSearch
iNaturalist (observations)
USDA Plants Database
LBJ Wildflower Center
SEINet
Plants of the World Online
Encyclopedia of Life
Wikipedia
Google Image Search

Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).

Choose a data source: Flora of North America, OregonFlora, UW Burke Herbarium

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Flora of North America species comparison

Oxalis oregana

Oxalis caerulea

Oxalis oregana

Oxalis caerulea