Fl. N. Amer. 1: 131. 1838.
Herbs annual, usually single-stemmed, rarely multi-stemmed, 2–5 dm, unbranched or few branched distally; from taproot, sometimes becoming fibrous root cluster. Stems erect, glabrous. Leaves alternate; sessile or subsessile; blade linear to narrowly elliptic proximally, or linear-subulate distally, 6–23 × (0.5–)1(–2) mm, base cuneate, apex acute to acuminate, surfaces glabrous. Racemes capitate to densely cylindric, 0.7–3(–4) × 0.6–1.3 cm; peduncle 0.3–2 cm; bracts persistent, often with scattered deciduous ones as well, lanceolate-ovate. Pedicels 0.7–1.6 mm, glabrous. Flowers pink or pale purple, 2.8–4 mm; sepals ovate or lanceolate-ovate, 0.6–1.3 mm; wings ovate or elliptic, 2.5–3.3(–3.8) × 1.7–2 mm, apex obtuse to bluntly rounded; keel 2.8–4 mm, crest 2-parted, with 1 lobe on each side, other lobes reduced to low, blunt processes. Capsules subglobose, 1.5–2.3 × 1.5–2.3 mm, margins not winged. Seeds 1–1.5 mm, pubescent; aril 0.5–0.8 mm, lobes 1/3–1/2 length of seed. 2n = 72.
Phenology: Flowering spring–summer.
Habitat: Wet flatwoods, bogs.
Elevation: 0–100 m.
Ala., Fla., Ga., La., Miss.
Polygala chapmanii occurs almost exclusively in the coastal counties (or one county removed) of the Gulf Coast, from eastern Louisiana to northwestern Florida, with the exception of an outlying occurrence in Georgia and a few counties in Alabama.