Amorpha canescens, Lead-plant, leadplant amorpha, prairie shoestrings

Lead plant is scientifically known as Amorpha canescens is a small, perennial semi-shrub in the pea family (Fabaceae). The plant is native to areas in Manitoba and Ontario. In the U.S. it occurs from Montana east to Michigan, and south to New Mexico and Louisiana. The plant has got several common names including lead-plant, leadplant amorpha, downy indigo bush, prairie shoestrings, buffalo bellows, Amorpha brachycarpa, Downy false indigo, and wild tea. Genus name comes from the Greek word amorphous meaning shapeless or deformed in reference to the corolla of this pea family genus lacking wings and a keel. The species cancers is from Latin and refers to the whitish or hoary color tinge from the fine leaf and stem hair and from which comes the common name of ‘lead’ plant. The alternate name ‘Devil’s Shoestrings’ comes from the deep roots that farmers were never able to plow out. The common name of lead plant refers to the once held belief that the plant was an indicator of the presence of lead in the ground. Some tribes named the plant “buffalo bellows” because the timing of flowering coincided with the time of the year that the buffalo were in rut and bellowing.

Plant Description

Lead plant is a sprawling, semi-erect, subshrub to herbaceous perennial plant that grows about 1 to 3.5 feet (0.3-1.1 m) tall. The plant is found growing in mesic to dry black soil prairies, sand prairies, gravel prairies, hill prairies, limestone glades, woodland and black oak savannas and remnant oak barrens. Leadplant is not particular about soil type, and it will flourish in loamy, sandy, gravelly, or clay soil. The plant has taproot and secondary lateral and vertical roots. Roots are branched and typically deeper than those of related bunchgrasses. It grows up to 5 m (16 ft.) deep and can spread up to 1 meter (3 ft. 3 in) radially. They may penetrate 7 to 20 feet (2-5 m), depending on the soil. Stem is ascending to erect, woody below, multiple from base, typically simple, canescent above, sparsely pubescent to glabrescent below, and striate-nerved. New stems are green and finely hairy which become woody with age.

Leaves

The leaves are compound, pinnately divided into 13 to 25 pairs of leaflets plus a terminal leaflet. Leaflets are generally oval to egg-shaped, rounded at both ends, about 1/2 inch long and half as wide. The leaf undersides and stems are covered with small whitish hairs, which as the leaf ages give the plant a grayish hue, hence the common name referring to ‘lead’. The prominent central leaflet vein extends beyond the rounded tip of the leaflet, forming a sharp point.

Inflorescence

The inflorescence consists of spike-like clusters (5 to 20) of small flowers at the ends of the stems. The weight of the spikes tends to cause the plant to tilt over, making it ‘semi-erect’.

Flower

The flowers are 5-parted, less than ¼ inch long with a 5-toothed purplish hairy calyx and a corolla which has a single petal that forms first a tube and then opens horizontally; initially shielded beneath it is the 8 stamens, pistil, and style. This petal is the typical banner petal of a pea family flower. The laterals and keel petals are missing. The corolla varies from light purple to deep blue-violet. The bulging bright stamens are quite noticeable with reddish filaments and yellow-orange anthers. One plant typically has 5 or more spikes at the end of branching stems, the terminal spike being longer than the surrounding spikes. Flowers bloom from the bottom of the spike up. Flowering normally takes place from July to September.

Fruit and seed

Fertile flowers are followed by modified oblong, curved legumes 3-4 mm long, 1.2-1.5 mm wide, slightly flattened, exerted beyond the persistent calyx tube, hairy and gland-dotted, 1-seeded. Seed is a smooth brown bean 2.0-2.4 mm long, 1.0-1.4 mm wide, olive to reddish-brown, oval with a slight hook at the tip. Seeds require a short period of cold stratification for germination.

Traditional uses and benefits of Lead plant

• An infusion of the leaves has been used to kill pinworms or any intestinal worms.
• The infusion is also used to treat eczema, the report does not say it if is used internally or externally.
• Dried and powdered leaves are applied as a salve to cuts and open wounds.
• Decoction of the root is used to treat stomach pains.
• A moxa of the twigs has been used in the treatment of neuralgia and rheumatism.
• Tea made from the leaves is used to treat ailments such as pinworms, eczema, rheumatism, neuralgia, open wounds, and cuts.
• Some indigenous tribes believed that the plant could aide in treating pinworms, eczema, rheumatism, neuralgia, open wounds, and cuts.

Other facts

• Plants have an extensive root system, they tolerate poor dry soils and are also wind resistant,
• They are used as a windbreak and also to prevent soil erosion.
• Resinous pustules on the plant contain ‘amorpha’, a contact and stomachic insecticide that also act as an insect repellent.
• Lead plant is an ideal ornamental species because it has showy flowers, is drought tolerant, and is shade tolerant.
• Dried leaves were used for smoking.

References