Alyssum petraeum Arduino, Animadv. Bot. Spec. Alt., 30. 1764

Plants slightly woody at base; finely stellate-pubescent. Stems: usually several, 1.5-6 dm. Basal leaves: petiole 0.3-2.5(-3.5) cm; blade obovate-oblong, 2.5-8 cm × 3-10 mm, base cuneate to attenuate, margins entire, sinuate, or pinnatifid, apex acute or obtuse, surfaces densely pubescent. Cauline leaves: blade oblanceolate to linear. Racemes considerably elongated in fruit. Fruiting pedicels 3-8 mm. Flowers: sepals yellowish, 1.5-2 × 0.5-1 mm, scarious at margins, finely pubescent; petals 3-4.5 × 1.2-2 mm, attenuate to clawlike base; filaments with basal wing or appendage to 0.5 mm, 1.2-2 mm; anthers 0.3-0.5 mm. Fruits divaricate-ascending, ellipsoid to obovoid, inflated at middle, slightly flattened at margin, 3-6 × 2-4 mm; style slender. Seeds winged throughout, 1.5-1.8 mm diam.; wing 0.1-0.3 mm wide. 2n = 16.

Flowering May-Jul. Cliffs, gorges, rocky slopes; introduced; N.Y.; s Europe.

Aurinia petraea is cultivated as an ornamental and is known to be naturalized in the gorge, Oneida (near Trenton Falls) and Ulster counties.