4. Polygala verticillata L. (whorled milkwort)

Pl. 495 f, g; Map 2265

Plants annuals, single-stemmed, with slender taproots. Stems 5–25(–40) cm long, erect or ascending, unbranched or few- to several-branched toward the tip, glabrous, not glaucous, green. Leaves at relatively widely spaced nodes, those of at least the lower 1–3 (often of nearly all) in whorls of 3–7, those of at least the uppermost nodes grading through opposite to alternate, 8–30 mm long, linear to narrowly oblong, narrowly elliptic, or narrowly oblanceolate, 1–3 mm wide, the margins entire, not shed early, the plants appearing leafy at flowering and fruiting. Inflorescences dense spikelike racemes or sometimes with relatively widely spaced flowers, at least toward the axis base, 1.0–2.5(–4.0) cm long. Wings 1.5–2.2 mm long, obovate to nearly oval, white, occasionally purplish-tinged, sometimes with a slender to broad green central band. Corollas 1.2–1.5 mm long, white, the fused portion 0.4–0.6 mm long. Fruits 1.8–2.5 mm long, oblong-ovoid, somewhat flattened. shallowly notched at the tip. Seeds 1.5–2.2 mm long, the aril 0.5–1.0 mm long, papery, with 2 linear lobes. 2n=34. May–October.

Scattered nearly throughout the state, but apparently absent from most of the Mississippi Lowlands Division (eastern U.S. west to Montana, Utah, and Texas; Canada; introduced in Asia). Glades, upland prairies, loess hill prairies, sand prairies, savannas, openings of mesic to dry upland forests, and banks of streams and spring branches; also pastures, old fields, and fallow fields.

Steyermark (1963) followed some earlier authors in accepting five varieties of this species in Missouri, but noted that there was extensive morphological intergradation between some of these taxa. J. F. Burns (1986) presented a detailed account of the convoluted nomenclatural and taxonomic history of the P. verticillata complex, and his sensible treatment is here followed for Missouri plants until future research can shed more light on variation within the complex.