American lopseed

American lopseed is a 12″ to 36″ tall, erect, perennial forb that rises from a somewhat fleshy, brownish root.

The stems are erect, 4-angled, jointed, and unbranched or sparingly branched. They are light green to dark purple, with a dark purple, swollen area above each node. The lower part of the stem is covered with short, soft, straight hairs, the upper portion with long, soft, straight hairs, especially at the nodes.

The leaves are opposite, egg-shaped, asymmetrical, 1 3 ⁄16″ to 4″ long, and ⅝″ to 2″ wide. Lower leaves are abruptly narrowed at the base with the blade continuing down along both sides of the leaf stalk to form a minute wing. They are on leaf stalks that are up to 1⅜″ long. The lowest leaves on the stem are smaller and are broadly egg-shaped. The upper and lower surfaces are rough to the touch due to a sparse covering of short, straight, stiff hairs. The margins are coarsely toothed. The leaf stalks become gradually shorter as they ascend the stem. Upper leaves are on leaf stalks that are 1 ⁄16″ to ⅛″ long. The uppermost leaves may be stalkless.

The inflorescence is a spike-like raceme at the end of the stem and branches and also from upper leaf axils. The racemes are 6″ to 13¾″ long. The central axis of the raceme (rachis) is dark purple and rough with firm, stiff hairs. Flowers appear on the rachis in opposite pairs. Flower buds are held erect. When in bloom the flowers are held horizontally.

Each flower is about ⅓″ and about ¼″ wide. At the base of the flower are 3 small awl-shaped bracts. There are 4 green sepals united at the base into a 1 ⁄16″ long calyx tube, then separated into 3 long, linear, purple, upper teeth and 2 much smaller lower teeth. There are 4 pale purple or pink to white petals united into a tube at the base then separated at the tip into 2 lips. The upper lip is small, straight, rounded, and notched at the tip. The lower lip is much longer, spreading, and 3-lobed. There are 2 long and 2 short pairs of stamens that do not extend beyond the corolla. The filaments are white and the anthers are pale yellow. There is a white style that does not protrude from the corolla. The stigma has 2 plate-like structures (lamellas) with sensitive inner surfaces that close together on contact with a pollinator.

After blooming the corolla drops off and the developing fruit bends downward, pressed tightly to the stalk, within the elongated, persistent calyx. The fruit is a single achene with a hooked tip.

12″ to 36″

Pale purple or pink to white

Moist. Woods, forests.

July to August

Sources

2, 3, 5, 7, 24, 28, 29, 30.

Biodiversity occurrence data published by: Minnesota Biodiversity Atlas (accessed through the Minnesota Biodiversity Atlas Portal, bellatlas.umn.edu, 6/9/2025).

Native

Common

Plant

Flowers

Plant

Inflorescence

Inflorescence

Inflorescence

Inflorescence

Leaves

Infructescence

Infructescence

Phryma leptostachya
Corey Raimond

Hello, Phryma!
Tales from Greenhouse

Location: Lebanon Hills Regional Park