Oxalis stricta
Oxalis bowiei
common yellow oxalis, common yellow wood sorrel, European wood-sorrel, upright yellow oxalis, upright yellow wood-sorrel, yellow woodsorrel
bowie's wood-sorrel, red-flower wood-sorrel
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.
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.
basal, rarely absent at flowering;
petiole (4–)6–16 cm, densely glandular-puberulent;
leaflets 3, green to purplish abaxially, green adaxially, obcordate, (12–)30–60 mm, lobed 1/6–1/3 length, lobes apically convex, often fleshy, surfaces densely glandular-puberulent, oxalate deposits absent.
usually regular cymes, rarely irregular cymes, (1–)5–7(–15)-flowered;
peduncles 3–9(–11) cm.
umbelliform cymes, 4–12-flowered;
scapes 15–20 cm, densely glandular-puberulent.
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.
heterostylous;
sepal apices without tubercles;
petals greenish yellow basally, pink to deep rose pink or red distally, 15–20 mm.
± cylindric, nearly terete, abruptly tapering to apex, 8–15 mm, villous to puberulent or glabrate, hairs septate.
not seen.
brown, transverse ridges rarely white.
= 18, 24.
Oxalis stricta
Oxalis bowiei
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.)
Oxalis bowiei is a naturalized garden escape in Oroville (Butte County; V. H. Oswald and L. Ahart 1994). Oxalis bowiei Aiton ex G. Don, from the Cape of Good Hope, was described as hoary-pubescent with peduncles about equal in length to the leaves and with red flowers. It perhaps is not the same species as O. bowiei Herbert (1833), provenance unspecified, but the color illustration clearly shows the commonly cultivated plant of contemporary commerce. Apparently neither name has been typified.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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