American lopseed

(Phryma leptostachya)

Conservation Status
American lopseed
  IUCN Red List

not listed


N5 - Secure

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

FACU - Facultative upland


UPL - Obligate upland

  Northcentral & Northeast

FACU - Facultative upland


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, 13 16 to 4 long, and 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 1 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 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 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


Flower Color


Pale purple or pink to white


Similar Species


Moist. Woods, forests.




July to August


Pests and Diseases






Distribution Map



2, 3, 4, 5, 7, 24, 28, 30.









  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  


Lamiales (mints, plantains, olives, and allies)  


Phrymaceae (lopseed)  
  Genus Phryma  



Phryma leptostachya var. asiatica

Phryma leptostachya var. confertifolia

Phryma media

Phryma parvifiora

Phryma pubescens


Common Names


American lop-seed

American lopseed














A dry, one-chambered, single-seeded seed capsule, formed from a single carpel, with the seed attached to the membranous outer layer (wall) only by the seed stalk; the wall, formed entirely from the wall of the superior ovary, does not split open at maturity, but relies on decay or predation to release the contents.



The group of outer floral leaves (sepals) below the petals, occasionally forming a tube.



A collective name for all of the petals of a flower.



Long, straight, and narrow, with more or less parallel sides, like a blade of grass.



The small swelling of the stem from which one or more leaves, branches, or buds originate.



An unbranched, elongated inflorescence with stalked flowers. The flowers mature from the bottom up.



An outer floral leaf, usually green but sometimes colored, at the base of a flower.

Visitor Photos

Share your photo of this plant.

  This button not working for you?
Simply email us at
Attach one or more photos and, if you like, a caption.

Kirk Neslon



    American lopseed      


    American lopseed      


    American lopseed   American lopseed  


    American lopseed   American lopseed  
    American lopseed      


    American lopseed      


    American lopseed   American lopseed  



Phryma leptostachya
Corey Raimond
  Phryma leptostachya  



Visitor Videos

Share your video of this plant.

  This button not working for you?
Simply email us at
Attach a video, a YouTube link, or a cloud storage link.


Other Videos
  Hello, Phryma!
Tales from Greenhouse

Aug 19, 2020

Phryma leptostachya, lopseed, ハエドクソウ (haedo-kusoo)






Last Updated:

© All rights reserved.

About Us

Privacy Policy

Contact Us