Virginia Tech Weed Identification Guide

Calepina: Calepina irregularis

calepina3-19e.jpg (154342 bytes) Weed Description:  An erect winter annual that produces a basal rosette of leaves and leaves that occur along a flowering stem.  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.
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. calepina3-14.jpg (161905 bytes)
calepina3-19c.jpg (62527 bytes) Stems:  Erect, branching, ranging from 4 to 20 inches in height but usually around 4-8 inches.  Stems are mostly without hairs but may have a few hairs toward the base.
Flowers:  Occur in clusters at the ends of the erect flowering stems.  Each flower occurs on a flower stalk (peduncle) and is white in color.

Fruit:   A silique.  Siliques contain a single seed.

calepina4-29.jpg (101213 bytes)
calepina6-4.jpg (15349 bytes) Roots: A taproot and fibrous root system.
Identifying Characteristics:   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 (Cardamine hirsuta), however the leaves of this weed have round leaflets arranged alternately along the central leaf stem unlike the leaves of calepina. calepina4-8b.jpg (126196 bytes)