Wood Betony (Common Lousewort)

Pedicularis canadensis

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Photo of wood betony plants with flowers
Julianna Schroeder
Family

Orobanchaceae (broomrapes); formerly Scrophulariaceae (figworts)

Description

Often in large colonies. Flowers in dense terminal clusters on unbranched stalks, light yellow, sometimes tinged with pink or purple, 2-lipped, the upper much longer than the lower, curving over the stamens. Each flower subtended by an oblong, leaflike bract. Blooms April-May. Leaves pinnately lobed, fernlike. Basal and most stem leaves on long petioles; stem leaves alternate. At least the upper part of the plants hairy. In early spring the emerging leaves have a beautiful wine-red color.

Similar species: Swamp wood betony or swamp lousewort (P. lanceolata) flowers in summer and fall, grows in swampy open meadows and limey soils, and is most common in the southeastern Ozarks; its stem leaves are usually opposite; and the upper part of the stem is not hairy.

Size

Height: to 10 inches when flowering; growing taller later.

Habitat and conservation

Occurs in dry and open woodlands, prairies, shaded glades, bottomlands, streamsides, and wooded valleys; often in leached or acid soils.

image of Wood Betony Common Lousewort distribution map
Distribution in Missouri

Statewide; absent from some southeastern counties.

Human connections

Many plants in this genus are called “lousewort” from an antique belief that cattle would be plagued with lice if they ate these plants. There is something parasitic about this plant, however: It is a root parasite on other plants.

Ecosystem connections

In addition to its taproot, wood betony sends out side roots that can attach to the roots of nearby plants such as grasses and tap nourishment from them. It can grow without host plants, however.