3. Oxalis florida Salisb. (yellow wood sorrel)

O. dillenii Jacq. ssp. filipes (Small) G. Eiten

O. filipes Small

Pl. 474 k; Map 2168

Plants perennial, but flowering the first year and often appearing annual, with taproots, usually lacking dark rhizomes, but sometimes developing stolons with age, lacking bulbs. Aerial stems 1(2), 5–20(–30) cm long, usually erect or strongly ascending, not rooting at the nodes, sparsely (often nearly glabrous) to moderately pubescent with fine, spreading to upward-curved, unicellular hairs, the pubescence sometimes somewhat denser near the stem base. Leaves basal and alternate, sometimes appearing fasciculate from the stem nodes, the petiole glabrous or sparsely pubescent with appressed to strongly ascending hairs. Stipules absent or, if present, then represented by slight thickenings or inconspicuous wings at the petiole base, these green. Leaflets 4–15 mm long, obcordate, the apical notch to 1/3 of the total length, the upper surface glabrous, the undersurface sparsely to moderately pubescent with mostly appressed hairs, yellowish green to grayish green, usually lacking purplish to brownish markings. Inflorescences umbellate with 2 or 3(–5) flowers, sometimes reduced to a solitary flower. Sepals 3–6 mm long, oblong-lanceolate to narrowly oblong-elliptic, green or translucent at the tip. Petals 5–11 mm long, yellow. Fruits 8–15 mm long, cylindrical at maturity, glabrous or sparsely pubescent with minute, curved hairs, sometimes mostly along the sutures. Seeds 1–2 mm long, brown, the ridges grayish or whitened. 2n=16. April–September.

Uncommon in the southeastern portion of the Ozark Division; known thus far from relatively few specimens collected in Bollinger, Butler, Carter, Ripley, and Wayne Counties (eastern U.S. west to Missouri, Arkansas, and possibly Texas). Bottomland forests, mesic upland forests, and margins of ponds and lakes.

Eiten (1963) and D. B. Ward (2004) considered this taxon a subspecies of O. dillenii. The two are closely related and future taxonomic studies may support this view. Oxalis dillenii is most easily distinguished from O. florida when fruits are present. At least in Missouri, where populations are disjunct from the main center of distribution for the species, plants of O. florida also tend to be rather slender-stemmed, delicate plants that do not appear to form well-developed rhizomes.