lyre-leaved rock cress

Lyre-leaved rock cress 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.

4″ to 16″

White or greenish white

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.

Dry. Woods, fields, sand dunes.

April to July

This and other mustards (family Brassicaceae) produce chemical compounds when cells are damaged that are toxic to most animals, fungi, and bacteria.

Sources

2, 3, 4, 5, 7, 24, 28, 29, 30.

Native

A recent study (German et al., March 2023) proposed a new and “novel” classification scheme for the family Brassicaceae. The authors divided the family into two subfamilies, five supertribes, and 58 tribes. A later study (Hendricks et al., October 2003) presented a new complete evolutionary history (phylogeny) of Brassicaceae based on molecular DNA. The later study strongly supports the reordering.

In the new classification, Arabidopsis is the only genus in the new tribe Arabidopsideae.

Bird’s Foot Violet, Hairy Puccoon, and Lyre Leaved Rock Cress

Plant

Inflorescence

Location: Kellogg Weaver Dunes SNA, Weaver Dunes Unit

Location: Vetsch Park

Location: Kellogg Weaver Dunes SNA, Weaver Dunes Unit

Bird’s Foot Violet, Hairy Puccoon, and Lyre Leaved Rock Cress

Location: Perrot State Park, Trempealeau WI