15. Oxalis suksdorfii Trelease, Mem. Boston Soc. Nat. Hist. 4: 89. 1888.
Western yellow wood-sorrel Western yellow wood-sorrel
Xanthoxalis suksdorfii (Trelease) Small
Herbs perennial, caulescent, rhizomes present <long>, stolons absent, bulbs absent. Aerial stems 1(–3) from base, mostly erect, 10–25 cm, herbaceous, sparsely to moderately villous, <hairs nonseptate and usually septate>. Leaves cauline; stipules rudimentary; petiole (2–)3–5(–6) cm, <hairs septate and nonseptate>; leaflets 3, green, obcordate, (8–)10–16(–20) mm, lobed 1/5–1/3 length, <margins green>, surfaces glabrous to sparsely strigose, oxalate deposits absent. Inflorescences umbelliform cymes, 1–3-flowered; peduncles (2–)4–8(–10) cm. Flowers tristylous, <above level of leaves>; sepal apices without tubercles; petals yellow, 12–20 mm. Capsules oblong-cylindric, 10–15 mm, densely puberulent. 2n = 24.
Flowering May–Aug. Open woods, fir, Douglas fir-oak woodlands, dry shrublands, roadsides, disturbed areas; 0–700 m; B.C.; Calif., Oreg., Wash.