This southeastern annual occurs mostly on sandy soils on lowlands and uplands from Mass. to Ga., but with scattered disjunct occurrences reported west to Ark. (W). For Ky. the only records are two colls. of B (#3661 in 1940 and #4106 in 1941) from "moist flats in barren...west of Knob Lick" in METC ( US); this should be rechecked. Reports from BATH, BELL and ROWA have been based on misidentified curtissii or mariana (M). P. nuttallii differs from curtisii (W) in its shorter lateral sepals (2-2.5 mm versus 3-5 mm), shorter pedicels (0.5-1.5 mm versus 1.5-2.5 mm), and narrower racemes (5-6 mm versus 8-13 mm).