Oxalis articulata
Oxalis dillenii
pink oxalis, pink sorrell, windowbox wood-sorrel
common yellow wood-sorrel, Dillen's oxalis, graygreen sorrel, slender yellow wood-sorrel, southern yellow wood-sorrel
(1–)2–8 from base, erect initially, often becoming decumbent or prostrate and stolonlike, rarely rooting at nodes, 10–25 cm, usually herbaceous, sometimes becoming woody proximally, densely and evenly strigillose to strigose from base to peduncles and pedicels, hairs straight, antrorsely appressed, nonseptate, sharp-pointed.
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.
basal and cauline;
stipules oblong, margins narrowly flanged or without free portions, apical auricles absent;
petiole 1–4 cm, hairs nonseptate;
leaflets 3, green, obcordate, (4–)6–15(–21) mm, lobed 1/5–1/3 length, abaxial surface sparsely strigillose, adaxial surface glabrous, oxalate deposits absent.
usually umbelliform cymes, less commonly in irregular cymes, 3–12-flowered;
scapes 12–28 cm, sparsely strigose.
usually umbelliform cymes, rarely irregular cymes, 1–3(–8)-flowered;
peduncles 1–6(–10) cm.
heterostylous;
sepal apices with 2 orange tubercles;
petals usually purplish rose to red, rarely white, 10–14 mm.
mostly homostylous;
sepal apices without tubercles;
petals yellow, without red lines, (2.5–)4–8 mm.
ovoid, 4–8 mm, sparsely strigose.
angular-cylindric, abruptly tapering to apex, 12–20(–25) mm, densely strigose-pilose, hairs both appressed and spreading, with puberulent understory.
brown, transverse ridges with strong grayish or white lines.
= 42.
= 18, 20, 22, 24.
Oxalis articulata
Oxalis dillenii
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.)
Decumbent stems of Oxalis dillenii often appear stolonlike, producing erect branches and leaves at the nodes, rarely producing a few adventitious roots. Such plants sometimes are misidentified as O. corniculata, but they differ in their overall habit, stems and rhizomes that become woody, reduced stipules, strigillose cauline vestiture, denser fruit vestiture, and seed color. Plants of O. dillenii in Canada and the western United States appear to be adventive.
Plants of Oxalis dillenii flowering into November and December in Texas and North Carolina, and probably elsewhere, characteristically are depressed in habit, with creeping stems and forming matlike colonies. The corollas are small, with petals 2.5–3 mm. Although similar in habit to typical O. corniculata, these plants do not have stems that root at nodes, and the strigillose vestiture, though reduced in density, and the stipule morphology are like O. dillenii. Whether these are the same genotype as spring-flowering plants or a different entity remains to be investigated. At least some of the variability in O. dillenii, particularly in habit, may be genetically partitioned, as dysploid chromosome races apparently exist.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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