prairie peppergrass

(Lepidium densiflorum)

Conservation Status
prairie peppergrass
  IUCN Red List

not listed


NNR - Unranked

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

FAC - Facultative


FAC - Facultative

  Northcentral & Northeast

FACU - Facultative upland


Prairie peppergrass is a 8 to 20 tall, erect, annual or biennial forb that rises on usually a single stem from a slender, branching taproot.

At first it forms a rosette of basal leaves about 6 in diameter. The basal leaves are 1½ to 2¾ long and either coarsely toothed or untoothed and once lobed. When the plant is a biennial it overwinters in this form. Basal leaves are usually wilted by flowering time.

The flowering stems are erect or ascending. They are occasionally branched at the base, often branched in the upper third. They are covered with minute, straight, spreading hairs.

Lower stem leaves are similar to the basal leaves, alternate, narrowly inversely egg-shaped or linear, 1 to 3 long, and less than wide. They are on short leaf stalks and are sometimes lobed but are usually unlobed. The leaf blades are tapered at the base and taper to a point at the tip with straight sides along the tip. The upper surface is hairless. The lower surface is usually hairless, sometimes sparsely minutely hairy. The margins are usually untoothed.

Upper stem leaves are similar but smaller, linear, and stalkless but not clasping.

The inflorescence is a dense, unbranched cluster (raceme) at the end of the stems and branches. The racemes are compact when in flower, but quickly elongate as the fruits develop, eventually becoming up to 4 long. Typically, a few flowers are in bloom crowded at the top of the raceme, with developing and developed fruits below.

The individual flowers less than wide. There are 4 green, linear to narrowly elliptic sepals, and either 4 white petals or no petals at all. When petals are present they are no longer than the sepals. There is no floral scent.

The fruit is a flattened, 1 16 to long, broadly egg-shaped, seed pod. It is widest above the middle. The tip is narrowly winged and has a broad, shallow notch. It is initially green, turning brownish when dry. It is on a stalk that is spreading or ascending.




8 to 20


Flower Color


White petals when present, otherwise green sepals.


Similar Species


Clasping pepper grass (Lepidium perfoliatum) upper stem leaves are broadly egg-shaped to circular and perfoliate or strongly clasping with auricles that surround the stem and overlap.

Field pennycress (Thlaspi arvense) fruits are much larger, 5 16 to ¾ long, and are broadly winged all around, not just at the tip.

Gardencress pepperweed (Lepidium sativum) fruits are on stalks that are closely ascending or almost erect. The fruits are larger, 3 16 to ¼ wide.

Virginia pepper grass(Lepidium virginicum var. virginicum) is nearly indistinguishable when not in flower. The flowers always have petals. The petals are as long to twice as long as the sepals. The fruits are mostly round, widest at the middle.


Dry to moist. Disturbed sites, roadsides, pastures.




May to June


Pests and Diseases




Defense Mechanisms


This and other mustards (family Brassicaceae) produce chemical compounds when cells are damaged that are toxic to most animals, fungi, and bacteria.




Distribution Map



2, 3, 4, 5, 7, 22, 28, 29, 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 Rosanae  


Brassicales (mustards, capers, and allies)  


Brassicaceae (mustard)  
  Tribe Lepidieae  


Lepidium (peppergrass)  

Subordinate Taxa


Several varieties of prairie peppergrass have been described. The varieties are not geographically separated, and characteristics used to define them are weak and differ among authors. For these reasons most taxonomists do not recognize any varieties of prairie peppergrass.




Lepidium densiflorum var. densiflorum

Lepidium densiflorum var. elongatum

Lepidium densiflorum var. macrocarpum

Lepidium densiflorum var. pubecarpum

Lepidium densiflorum var. ramosum

Lepidium densiflorum var. typicum

Lepidium elongatum

Lepidium neglectum

Lepidium pubecarpum

Lepidium ramosum

Lepidium texanum


Common Names


common peppergrass

common peppergweed

green-flowered peppergrass

miner’s pepperweed

miner’s pepperwort



prairie peppergrass

prairie pepperweed

prairie pepperwort













A small, ear-like projection at the base of a leaf or at the junction of a grass blade and stem.



Describing a leaf that wholly or partly surrounds the stem but does not fuse at the base.



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



A leaf having margins that entirely surround the stem, giving the appearance that the stem is growing through the leaf.



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





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    prairie peppergrass   prairie peppergrass  


    prairie peppergrass      


    prairie peppergrass   prairie peppergrass  



  Lepidium campestre FIELD CRESS
Frank Mayfield
  Lepidium campestre FIELD CRESS  



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Antelope Valley SNA

Bertram Chain of Lakes Regional Park

Big Stone Lake State Park

Blazing Star Prairie

Blazing Star Prairie Addition Preserve, South Unit

Blue Mounds State Park

Bunker Hills Regional Park

Cambria WMA

Camden State Park

Cedar Mountain SNA

Chippewa Prairie

Cottonwood River Prairie SNA

Crow-Hassan Park Reserve

Felton Prairie SNA, Bicentennial Unit

Franconia Bluffs SNA

Frenchman’s Bluff SNA

Frontenac State Park

Hemlock Ravine SNA

Holthe Prairie SNA

Kellogg Weaver Dunes SNA, Kellogg Weaver Unit

Kilen Woods State Park

Lebanon Hills Regional Park

Lester Lake SNA

Maplewood State Park

Margherita Preserve-Audubon Prairie

McKnight Prairie

Mille Lacs Kathio State Park

Miller Prairie, West Unit

Minnesota Valley NWR, Rapids Lake Unit

Mississippi River County Park

Morton Outcrops SNA

Mound Spring Prairie SNA, North Unit

Northern Tallgrass Prairie NWR, Spieker Unit

Northern Tallgrass Prairie NWR, Touch the Sky Prairie Unit

Ordway Prairie

Otter Tail Prairie SNA

Pankratz Memorial Prairie, North Unit

Phelps Lake WMA

Pilot Knob

Pine Bend Bluffs SNA

Prairie Creek WMA, Koester Prairie Unit

Regal Meadow

River Terrace Prairie SNA

River Warren Outcrops SNA

Rock Ridge Prairie SNA

St. Croix State Park

Sand Prairie Wildlife Management and Environmental Education Area

Savage Fen SNA

Schaefer Prairie

Split Rock Creek State Park

Spring Lake Park Reserve

Swedes Forest SNA

Tiedemann WMA

Tribute WMA

Twin Valley WMA: North Unit

Uncas Dunes SNA

Upper Sioux Agency State Park

Vermillion River WMA

Whitetail Woods Regional Park

Wild River State Park







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