Know Your Natives – Cut-Leaf Toothwort

Cut-leaf toothwort (Cardamine concatenata) of the Mustard (Brassicaceae) family occurs throughout the eastern U.S., westward to eastern Texas, eastern South Dakota, but is uncommon in Georgia and Florida at the southeastern extent, as well as in the northeastern reaches of New England.  In Arkansas, the species occurs in upland areas across the state, including Crowley’s Ridge.  The genus name is from the Greek word for a type of cress.  The specific epithet means “linked together” in reference to the character of its roots.  This toothwort was formerly classified as Dentaria laciniata.  Common names of this plant also include pepper-root and crow’s-toes.

Cut-leaf toothwort is a spring ephemeral with shallow, jointed, horizontal rhizomes composed of tooth-like segments.  Segments are spindle shaped (fusiform), generally less than ½ inch in diameter.  It grows in rich, well-drained but mesic soils of open deciduous woodlands found in river and stream bottoms and slopes with thick leaf litter.  It may form colonies.  Growing to about 12 inches tall, cut-leaf toothwort goes from emergence to flowering, fruiting and then dormancy in four to five weeks.

Cut-leaf toothwort, at emergence, tends to have overall pinkish coloration overshadowing its later green color.  Mature leaves are gray-green.  Single rhizomal leaves grow directly from the rhizome and three whorled cauline leaves grow from flowering stems.  Rhizomal and cauline leaves have the same overall characteristics, including petioles.  However, petioles of rhizomal leaves are terete (round) in cross-section while petioles of cauline leaves are grooved along their upper length.

Toothwort - Cardamine concatenataPhoto 1:  Flowering stems with leaves emerge with a pinkish coloration.

Leaves, to 3 inches long and wide, are glabrous to sparsely pubescent and with three leaflets.  Terminal leaflets are oblong to linear with jagged deeply cleft margins creating very long, narrow lobes.  Leaflets have dominant central veins and acutely angled lateral veins along with course-jagged teeth angled toward apexes of lobes.  Characteristics of two lateral leaflets are similar to terminal leaflets, but lateral leaflets are not as long.  All leaflet blades are slightly up-angled on either side of the central vein.  Details of leaf shape on a plant and on different plants are variable.  When the lateral leaflets have especially long lobes, such leaflets give the appearance of having five lobes.

A peduncle (stalk supporting the inflorescence) rises immediately above the cauline leaves as an extension of the stem.  Peduncles, continuing to grow as inflorescence develops, tend to be angled or bent from the stem.  With inflorescence at full bloom, stem and peduncle are about the same length.  Stems and peduncles have very short, dense hairs.

Toothwort - Cardamine concatenataPhoto 2:  Whorled cauline leaves surround emerging flower buds while a rhizomal leaf emerges at lower right.

Inflorescence, in late winter to early spring, is a terminal cluster of flowers in a loose bract-free raceme on relatively long, slender peduncles.  Flowers open from bottom of the raceme to the top, with fruit of lower flowers already present as upper flowers bloom.  Flowers are typically white at anthesis, but tend to be pinkish in bud.  However, pink flowers at anthesis also occur.

Flowers are up to ½ inch across with four petals and four sepals.  Light green sepals, being oblong with obtuse tips and convex in cross-section, form a tubular calyx which firmly clasps the flower while blooming.  Petals, broadly lanceolate, are much longer than sepals and have rounded tips.  The center of a flower is greenish with six stamens and a single style with a round-topped stigma.  Stamens have greenish filaments of differing lengths and yellow anthers.

Toothwort - Cardamine concatenataPhoto 3:  At full bloom, light pink buds have become white flowers.  Stamens are of unequal length.

Toothwort - Cardamine concatenataPhoto 4:  A colony at full bloom.  Immature fruit can be seen on raceme at upper left.

Mature fruits are ascending, bean-like pods about 1½ inches long and 1/8 inch wide with long tapering tips.  Pods may contain up to a dozen flattened, brown seeds in a single row. When dry, the pod twists open to eject seeds after which plants quickly fade.

In a garden or woodland setting, cut-leaf toothwort’s small size and short-ephemeral nature may not make it an endearing plant.  However, where a small, shady, fertile space is available, toothwort should be welcome.  This perennial is a harbinger of spring which has interesting characteristics that can be counted on to reappear year after year.

In Arkansas, in addition to cut-leaf toothwort, at least nine other species of Cardamine occur, of which three are introduced.  Two native species that are most similar to cut-leaf toothwort are slender toothwort (Cardamine angustata) and fork-leaf toothwort (Cardamine dissecta).  Both are of limited occurrence in the state, being restricted to the western Ouachita Mountains.  In comparison to cut-leaf toothwort, slender toothwort has leaflets of rhizomal leaves that are broad and not dissected, and leaflets of cauline leaves that are also broader and less dissected.  Fork-leaf toothwort has highly dissected leaves such that they appear net-like.

Article and photographs by ANPS member Sid Vogelpohl

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