Flora of North America species comparison

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Oxalis articulata

Oxalis illinoensis

pink oxalis, pink sorrell, windowbox wood-sorrel

Illinois wood-sorrel
Habit Herbs perennial, acaulous, rhizomes present, thick, woody, irregularly nodulate-segmented, often covered with persistent petiole bases, stolons absent, bulbs absent. Herbs perennial, caulescent, rhizomes present, with horizontal, white, fusiform tubers or tuberlike thickenings, stolons absent, bulbs absent.
Aerial stems

1(–3) from base, erect, 15–40 cm, herbaceous, glabrate to sparsely to densely villous, hairs ± straight, spreading, septate and nonseptate.
Leaves

basal;

petiole 11–30 cm;

leaflets 3, green to purplish abaxially, green adaxially, rounded-obcordate, 18–20 mm, margins densely loosely ciliate, lobed 1/5–1/3 length, lobes apically convex, surfaces evenly strigose-villous to strigose-hirsute, oxalate deposits in dots concentrated mostly toward margins or over whole surface.

cauline;

stipules rudimentary;

petiole 4–7.5 cm, hairs septate and nonseptate;

leaflets 3, green, obcordate, (12–)20–30(–35) mm, lobed 1/5 length, lobes apically truncate, margins green, ciliate, surfaces glabrous, oxalate deposits absent.
Inflorescences

usually umbelliform cymes, less commonly in irregular cymes, 3–12-flowered;

scapes 12–28 cm, sparsely strigose.

regular or irregular cymes, 1–3(–6)-flowered;

peduncles 3–10 cm.
Flowers

heterostylous;

sepal apices with 2 orange tubercles;

petals usually purplish rose to red, rarely white, 10–14 mm.

tristylous, mostly at level of leaves;

sepal apices without tubercles;

petals yellow, with prominent red lines proximally, 12–18 mm.
Capsules

ovoid, 4–8 mm, sparsely strigose.

oblong-ovoid, 7–10 mm, sparsely puberulent to villous.
Seeds

brown, transverse ridges brown.
2n

= 42.

Oxalis articulata

Oxalis illinoensis
Phenology Flowering Mar–Jul. Flowering Apr–Sep.
Habitat Disturbed places, especially near gardens, lawns, fields, roadsides. Slopes, bluffs, ravines, flood plains, mesic forests, sometimes forming dominant ground cover, commonly on limestone, shale, or calcareous loess.
Elevation 0–250 m. (0–800 ft.) 200–500 m. (700–1600 ft.)
Distribution
from FNA
AL; AR; CA; FL; GA; LA; MS; NC; OK; OR; SC; TX; VA; South America (Argentina, Brazil, Uruguay) [Introduced in North America; introduced also in Europe, Pacific Islands (New Zealand), Australia]
[WildflowerSearch map]
[BONAP county map]
from FNA
IL; IN; KY; TN
[BONAP county map]
Discussion

Oxalis articulata in the United States commonly has been identified as O. rubra. Oxalis rubra was treated at subspecific rank by A. Lourteig (1982), but subsp. articulata and subsp. rubra have essentially the same native range and occur in similar habitats. Lourteig identified both subspecies in the United States, noting in her key that vestiture is reduced and the sepals are broader in subsp. rubra. Evidence is weak for recognizing more than a single entity. In the Flora of Panama (Lourteig 1980), she recognized only O. articulata, noting that it is naturalized in other parts of America and in the Old World.

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

Differences between Oxalis illinoensis and O. grandis are subtle, but they appear to be correlated with geography. Oxalis illinoensis occupies the western part of the range of O. grandis in the wide sense. The tuberous portions of the rhizomes of O. illinoensis are diagnostic, but they are commonly broken off during collection. M. E. Medley (1993) observed that the two taxa intergrade, and a hybrid population has been identified in Indiana (A. L. Heikens 2003).

Oxalis illinoensis is listed as threatened in Illinois and rare in Indiana.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 12, p. 153. FNA vol. 12, p. 145.
Parent taxa Oxalidaceae > Oxalis Oxalidaceae > Oxalis
Sibling taxa
O. albicans, 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. stricta, O. suksdorfii, O. texana, O. triangularis, O. trilliifolia, O. violacea
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. 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. articulata subsp. rubra, O. rubra
Name authority Savigny: in J. Lamarck et al., Encycl. 4: 686. (1798) Schwegman: Phytologia 50: 467. (1982)
Web links 
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).



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