Scientific Name: Calepina irregularis

Common Name: white ballmustard

Synonyms: Myagrum irregulare

Leaves: Initially, plants develop a basal rosette of leaves. Basal leaves are oval to lanceolate in outline but widest at the apex of the leaf and tapering to the base. Basal leaves range from 3/4 to 4 inches in length and rarely reach more than 3/4 inch in width The basal leaves are deeply lobed and have a prominent white midvein. Leaves that occur along the flowering stems are much smaller than the basal leaves, ranging from 1/2 to 1 1/2 inches in length. These upper leaves are not lobed like those of the basal rosette, but have toothed margins. Leaves may be either without hairs (glabrous) or with a few hairs on the leaf undersides.

Identifying Characteristics: An erect winter annual that produces a basal rosette of leaves and leaves that occur along a flowering stem.The lobed basal leaves but unlobed stem leaves, winter annual growth habit, and small white flowers that occur in clusters at the ends of the flowering stems are all characteristics that help in the identification of Calepina. Calepina could easily be misidentified as Shepherd's-purse, however the young leaves of this weed usually have star-shaped hairs (branched hairs), the flowering stems do not have leaves, and the seed pods are triangular unlike those of calepina. Young calepina plants may also be confused with Hairy Bittercress (<a href='../../weedimg/274'>Cardamine hirsuta</a>), however the leaves of this weed have round leaflets arranged alternately along the central leaf stem unlike the leaves of calepina.

Flower Seed Head: Occur in clusters at the ends of the erect flowering stems. Each flower occurs on a flower stalk (peduncle) and is white in color.

Seed Fruit: A silique. Siliques contain a single seed

Where Found: This weed is fairly rare and has been introduced into both Virginia and North Carolina probably as a contaminant of alfalfa seed. Calepina is fairly localized to Goochland, Powhatan, Cumberland, and Amelia counties in Virginia and to Buncombe County in North Carolina. It is primarily a weed of alfalfa.

  • Life cycle: winter annual

  • Milky sap: Not Present

  • Plant type: Herb

  • Thorns: Not Present

  • Plant family: Brassicaceae

  • Leaf arrangement: rosette

  • Leaf shape: oval

  • Ochrea: Not Present

  • Leaf margin: lobed

  • Stem hairs: has hairs; no hairs

  • Flower color: white

  • Growth habit: upright and nonwoody

  • Stem: round or oval

  • Leaf structure: simple

  • Leaf hairs: no hairs

  • Flower diameter: pencil

  • Flower symmetry: disymetry

  • Root structure: taproot

  • Leaf stalk: shorter than leaf