FNA: Oxalis stricta

	Oxalis stricta
	common yellow oxalis, common yellow wood sorrel, European wood-sorrel, upright yellow oxalis, upright yellow wood-sorrel, yellow woodsorrel
Habit	Herbs annual or short-lived perennial, caulescent, rhizomes present, short, stolons absent, bulbs absent.
Aerial stems	1(–3) from base, erect or later leaning or falling over and decumbent, not rooting at nodes, 20–60(–90) cm, herbaceous, villous, hairs ± straight, spreading, usually nonseptate and septate, septate hairs commonly concentrated at nodes, very rarely only nonseptate.
Leaves	basal and cauline; stipules rudimentary; petiole 2–8 cm, hairs septate and nonseptate; leaflets 3, light green to yellowish green, obcordate, (8–)10–20(–30) mm, lobed 1/5–1/3 length, surfaces glabrous, oxalate deposits absent.
Inflorescences	usually regular cymes, rarely irregular cymes, (1–)5–7(–15)-flowered; peduncles 3–9(–11) cm.
Flowers	homostylous or slightly to strongly heterostylous, usually within or slightly above level of leaves; sepal apices without tubercles; petals yellow, without red lines, (6–)8–11 mm.
Capsules	± cylindric, nearly terete, abruptly tapering to apex, 8–15 mm, villous to puberulent or glabrate, hairs septate.
Seeds	brown, transverse ridges rarely white.
2n	= 18, 24.

	Oxalis stricta
Phenology	Flowering (Apr–)Jul–Oct.
Habitat	Prairie ravines, riverbanks, sandbars, low woods, mesic forests, floodplains, roadsides, fields, lawns, gardens.
Elevation	20–1200 m. (100–3900 ft.)
Distribution	AL; AR; AZ; CO; CT; DC; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NY; OH; OK; PA; RI; SC; SD; TN; VA; VT; WA; WI; WV; WY; BC; MB; NB; NF; NS; ON; PE; QC; SK [Introduced in Europe, Asia, Africa, Pacific Islands (New Zealand), Australia] [WildflowerSearch map] [BONAP county map]
Discussion	Oxalis stricta is uncommon and probably adventive in Canada and the western United States. The species is recognized by the combination of its tall (rarely up to nearly a meter), erect stems from a short, simple rhizome; septate hairs; cymose inflorescence; and small flowers. Septate hairs on the stems and petioles are easily recognized (lens) by their colored cross-walls, but they vary greatly in density. In villicaulis forms, the hairs are dense and evenly distributed, but in most plants over the range they are localized around the nodes and intermixed with nonseptate hairs. Often they are sparse; rarely they appear to be absent on plants with greatly reduced vestiture overall. A. Lourteig (1979) identified this species as Oxalis fontana, typified by a plant from northern China, and applied the name O. stricta to the species identified by G. Eiten (1955, 1963) and here as O. dillenii. The basis for the difference lies in selection of lectotypes. Choice of stricta as the correct epithet acknowledges that the description of O. stricta by Linnaeus best matches these plants and that selection of a Morison illustration as lectotype characterizes the species long-naturalized and weedy in Europe and probably known first-hand by Linnaeus. C. E. Jarvis (2007) has confirmed this choice of lectotype. Oxalis dillenii is appropriately lectotypified by a John Clayton collection from Virginia. The situation has been summarized well by D. B. Ward (2004). (Discussion copyrighted by Flora of North America; reprinted with permission.)
Source	FNA vol. 12, p. 143.
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. oregana, O. pes-caprae, O. pilosa, O. purpurea, O. suksdorfii, O. texana, O. triangularis, O. trilliifolia, O. violacea
Synonyms	O. bushii, O. coloradensis, O. cymosa, O. europaea, O. europaea var. bushii, O. fontana, O. fontana var. bushii, O. interior, O. rufa, O. stricta var. decumbens, O. stricta var. piletocarpa, O. stricta var. rufa, O. stricta var. villicaulis, Xanthoxalis bushii, X. cymosa, X. rufa, X. stricta
Name authority	Linnaeus: Sp. Pl. 1: 435. (1753)
Web links	Local floras: BC, WA Local Web sites: Flora NW, Go Botany, IL Wildflowers, KS Wildflowers, LA Plants, MD Biodiversity, MI Flora, MN Wildflowers, MO Plants, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Oxalis stricta

common yellow oxalis, common yellow wood sorrel, European wood-sorrel, upright yellow oxalis, upright yellow wood-sorrel, yellow woodsorrel

Habit

Herbs annual or short-lived perennial, caulescent, rhizomes present, short, stolons absent, bulbs absent.

Aerial stems

1(–3) from base, erect or later leaning or falling over and decumbent, not rooting at nodes, 20–60(–90) cm, herbaceous, villous, hairs ± straight, spreading, usually nonseptate and septate, septate hairs commonly concentrated at nodes, very rarely only nonseptate.

Leaves

basal and cauline;

stipules rudimentary;

petiole 2–8 cm, hairs septate and nonseptate;

leaflets 3, light green to yellowish green, obcordate, (8–)10–20(–30) mm, lobed 1/5–1/3 length, surfaces glabrous, oxalate deposits absent.

Inflorescences

usually regular cymes, rarely irregular cymes, (1–)5–7(–15)-flowered;

peduncles 3–9(–11) cm.

Flowers

homostylous or slightly to strongly heterostylous, usually within or slightly above level of leaves;

sepal apices without tubercles;

petals yellow, without red lines, (6–)8–11 mm.

Capsules

± cylindric, nearly terete, abruptly tapering to apex, 8–15 mm, villous to puberulent or glabrate, hairs septate.

Seeds

brown, transverse ridges rarely white.

= 18, 24.

Oxalis stricta

Phenology

Flowering (Apr–)Jul–Oct.

Habitat

Prairie ravines, riverbanks, sandbars, low woods, mesic forests, floodplains, roadsides, fields, lawns, gardens.

Elevation

20–1200 m. (100–3900 ft.)

Distribution

AL; AR; AZ; CO; CT; DC; DE; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NY; OH; OK; PA; RI; SC; SD; TN; VA; VT; WA; WI; WV; WY; BC; MB; NB; NF; NS; ON; PE; QC; SK [Introduced in Europe, Asia, Africa, Pacific Islands (New Zealand), Australia]

[WildflowerSearch map]

[BONAP county map]

Discussion

Oxalis stricta is uncommon and probably adventive in Canada and the western United States. The species is recognized by the combination of its tall (rarely up to nearly a meter), erect stems from a short, simple rhizome; septate hairs; cymose inflorescence; and small flowers. Septate hairs on the stems and petioles are easily recognized (lens) by their colored cross-walls, but they vary greatly in density. In villicaulis forms, the hairs are dense and evenly distributed, but in most plants over the range they are localized around the nodes and intermixed with nonseptate hairs. Often they are sparse; rarely they appear to be absent on plants with greatly reduced vestiture overall.

A. Lourteig (1979) identified this species as Oxalis fontana, typified by a plant from northern China, and applied the name O. stricta to the species identified by G. Eiten (1955, 1963) and here as O. dillenii. The basis for the difference lies in selection of lectotypes. Choice of stricta as the correct epithet acknowledges that the description of O. stricta by Linnaeus best matches these plants and that selection of a Morison illustration as lectotype characterizes the species long-naturalized and weedy in Europe and probably known first-hand by Linnaeus. C. E. Jarvis (2007) has confirmed this choice of lectotype. Oxalis dillenii is appropriately lectotypified by a John Clayton collection from Virginia. The situation has been summarized well by D. B. Ward (2004).

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

Source

FNA vol. 12, p. 143.

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. oregana, O. pes-caprae, O. pilosa, O. purpurea, O. suksdorfii, O. texana, O. triangularis, O. trilliifolia, O. violacea

Synonyms

O. bushii, O. coloradensis, O. cymosa, O. europaea, O. europaea var. bushii, O. fontana, O. fontana var. bushii, O. interior, O. rufa, O. stricta var. decumbens, O. stricta var. piletocarpa, O. stricta var. rufa, O. stricta var. villicaulis, Xanthoxalis bushii, X. cymosa, X. rufa, X. stricta

Name authority

Linnaeus: Sp. Pl. 1: 435. (1753)

Web links

Local floras: BC, WA
Local Web sites: Flora NW, Go Botany, IL Wildflowers, KS Wildflowers, LA Plants, MD Biodiversity, MI Flora, MN Wildflowers, MO Plants, PNW Herbaria
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, UW Burke Herbarium

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Oxalis stricta

Oxalis stricta