Oxalis articulata
Oxalis macrantha
pink oxalis, pink sorrell, windowbox wood-sorrel
Price's wood-sorrel
usually 2–8 from base, erect initially, usually becoming decumbent, 5–20(–40) cm, becoming woody proximally, hirsute-pilose on at least proximal 2/3, hairs curved, loosely and irregularly spreading, nonseptate.
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 2–7 cm;
leaflets 3, green, obcordate, 3.5–12 mm, lobed 1/5–1/3 length, surfaces usually strigose-hirsute, sometimes glabrate, oxalate deposits absent.
usually umbelliform cymes, less commonly in irregular cymes, 3–12-flowered;
scapes 12–28 cm, sparsely strigose.
umbelliform cymes, less commonly irregular cymes, (1–)3–8-flowered;
peduncles (3–)5–10(–15) cm.
villous, hairs long, spreading.
heterostylous;
sepal apices with 2 orange tubercles;
petals usually purplish rose to red, rarely white, 10–14 mm.
distylous, well above level of leaves;
sepal apices without tubercles;
petals yellow to yellow-orange, with prominent red lines proximally, (13–)15–20(–23) mm.
ovoid, 4–8 mm, sparsely strigose.
angular-cylindric, abruptly tapering to apex, 10–15 mm, sparsely to densely hirsute-pilose, hairs long, sometimes mostly along angles.
brown, transverse ridges usually white.
= 42.
Oxalis articulata
Oxalis macrantha
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.)
Oxalis macrantha is restricted mostly to limestone glades in Alabama, Kentucky, and Tennessee. It is recognized by its villous to villous-hirsute stems, flowers in umbelliform cymes, and large yellow to yellow-orange corollas with red lines proximally. The lines in the throat remain visible after drying and usually can be seen on herbarium specimens even from the outside of the flower. A similar pattern also occurs in other species, especially O. grandis, O. illinoensis, and O. texana.
Seemingly disjunct plants of native habitats in Nuevo León, Mexico, identified as Oxalis macrantha apparently are more common than reported by G. L. Nesom (2009b). Whether these are actually disjunct or a parallel morphological expression derived from some Mexican species needs to be investigated.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
OR
CalFlora
Flora NW
LA Plants
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
