50. Boechera laevigata (Muhlenberg ex Willdenow) Al-Shehbaz, Novon. 13: 386. 2003.
Turritis laevigata Muhlenberg ex Willdenow, Sp. Pl. 3: 543. 1801; Arabis hastata Eaton; A. heterophylla Nuttall; A. laevigata (Muhlenberg ex Willdenow) Poiret; A. lyrifolia de Candolle
Biennials; short-lived; sexual; caudex not evident. Stems 1 per plant, arising from center of rosette near ground surface, (1.5-)3-11 dm, glabrous throughout. Basal leaves: blade obovate to oblanceolate, (4-)10-40 mm wide, margins serrate or dentate, ciliate-mucronate on teeth, trichomes often minute, surfaces glabrous or sparsely pubescent, trichomes simple, 0.1-0.6 mm. Cauline leaves: 7-15, often concealing stem proximally; blade auricles 3-12 (-17) mm, surfaces of distalmost leaves glabrous. Racemes 16-45-flowered, sometimes branched. Fruiting pedicels suberect to divaricate-ascending, straight to slightly curved, 5-23 mm, glabrous. Flowers ascending at anthesis; sepals glabrous; petals white, 3-5 × 1-1.5 mm, glabrous; pollen ellipsoid. Fruits divaricate-ascending, not appressed to rachis, rarely somewhat secund, curved, edges parallel, (4-)6-11.7 cm × 1-2 mm; valves glabrous; ovules 50-80 per ovary; style 0.1-0.7(-1) mm. Seeds uniseriate, 1.2-2.2 × 0.8-1.4 mm; wing continuous, 0.1-0.3 mm wide distally. 2n = 14.
Flowering Mar-May. Rocky bluffs, cedar glades, wooded hillsides, floodplains; 100-500 m; Ont., Que.; Ala., Ark., Conn., Del., D.C., Ga., Ill., Ind., Iowa, Ky., Md., Mass., Mich., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Vt., Va., W.Va., Wis.
The taxon sometimes treated as Arabis laevigata var. missouriensis is here recognized as a separate species (Boechera missouriensis) based on its significantly longer petals (5-10 versus 3-5 mm) and distinctive, lyrate-pinnatifid basal leaves that persist well beyond anthesis.