1. Neslia paniculata (L.) Desv. (ball mustard)

Pl. 324 j, k; Map 1374

Plants annual, terrestrial, pubescent with 2- to several-branched hairs. Stems 25–70(–90) cm long, erect, usually few-branched toward the tip. Leaves alternate and usually also basal, 3–6 cm long, sessile, those of the stems clasping with prominent, pointed or narrowly rounded auricles, the blades oblanceolate to lanceolate in outline, the margins entire. Inflorescences racemes at the tips of the branches, the flowers not subtended by bracts. Sepals 1.0–1.5 mm long, oblong, ascending. Petals 1.5–2.5 mm long, not lobed, light yellow. Styles 0.5–1.0 mm long. Fruits spreading, 2.0–2.5 mm long, about as long as wide or slightly longer than wide, globose to depressed-globose, each valve with a coarse, netlike or honeycomb-like pattern of ridges and pits, indehiscent. Ovules 2 per locule. Seeds usually 1 per locule, 1.9–2.2 mm long, circular to broadly obovate in outline, the margins not winged, the surface with a coarse, netlike or honeycomb-like pattern of ridges and pits and also finely roughened, tan to dark brown. 2n=14, 28. May–July.

Introduced, uncommon, sporadic (native of Europe, sporadically introduced in the U.S. and Canada). Railroads.