Arabidopsis lyrata ssp. lyrata

Native

Dry. Woods, fields, sand dunes.

April to July

White or greenish white

4″ to 16″

This is a 4″ to 16″ tall, erect, biennial or perennial forb that rises from a taproot rhizome.

The stems are upright or ascending, branched from the base. The lower stem is covered with coarse, stiff hairs.

Basal leaves are lyre-shaped, with a large terminal lobe and lateral lobes progressively smaller toward the base. There is a pair of ear-shaped lobes at the base of the leaf. The leaves are ¾″ to 1½″ long and form a rosette.

Stem leaves are alternate, linear or narrowly spatula-shaped, widest at the blunt tip, narrowing to the base. The lowest stem leaves may have a few short teeth or lobes, the remaining are unlobed and untoothed. They are attached to the stem without leaf stalks.

The inflorescence is a short, loose, branched cluster at the end of the stem and branches.

The flowers are ¼″ to ½″ wide, with 4 white to greenish-white petals. They are on ¼″ to ⅔″ long, ascending, flower stalks. The petals are ⅛″ to ⅓″ long, much longer than the sepals. There are 6 stamens.

The fruit is a thin, flat pod, ¾″ to 1¾″ long, on a ¼″ to ⅔″ long stalk, spreading outward and pointing upward.

The rosette of lyre-shaped basal leaves, linear stem leaves, and large flowers are diagnostic for this species.

Mouse-ear cress (Arabidopsis thaliana) basal leaves are unlobed. The flowers are much smaller.