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Weed Identification

Broadleaf Weeds

Photo Gallery

These are some characteristics of broadleaf plants that will aid in identification.

 
  Ochrea's are papery sheaths found where the petiole attaches to the stem. This is characteristic of plants in the buckwheat family.

Leaves Alternate or Whorled   Leaves Opposite
Black medic Pineappleweed   Common chickweed Puncturevine
Broadleaf plantain Poison hemlock   Common milkweed Purple deadnettle
Buckhorn plantain Poison ivy   Giant ragweed Purslane
Burcucumber Pokeweed   Ground ivy Speedwell
Buttercup Prickly lettuce   Hemp dogbane Spurge
Butterweed Prickly sida   Henbit Sunflower
Canada thistle Prostrate knotweed   Honeyvine milkweed Wild four-o'clock
Catchweed bedstraw Red sorrel   Hophornbeam copperleaf  
Chicory Shepherdspurse   Mouseear chickweed  
Common burdock Smooth groundcherry      
Common cocklebur Spurred anoda      
Common lambsquarters Swamp smartweed   Cactus  
Common mallow Toothed spurge   Pricklypear  
Common ragweed Velvetleaf      
Curly dock Venice mallow      
Dandelion Virginia pepperweed   Broadleaf Weed Collections
Eastern black nightshade Wild buckwheat   Pigweed Species  
Field bindweed Wild carrot   Winter annual weed species
Field pennycress Yellow rocket      
Horsenettle        
Horseweed        
Ivyleaf morningglory        
Japanese knotweed        
Jimsonweed        
Kochia        
Pennsylvania Smartweed        

Grass and Grasslike Weeds

Photo Gallery

These are characteristics of grass and grasslike weeds that will aid in identification.

The ligule and collar region of the plant is where the main characteristics used for identification are located.

Stems

A

B

C
 
Grass leaves are either rolled (A) or flat (B) within the stem. Sedges can be identified by a triangular stem (C).  
Ligules and Auricles

A


B

C

D

Ligules of grasses will either be absent (A), hairy (B), or membranous (C and D).The absence and presence of auricles can be seen between images C and D.


Absent ligule   Hairy ligule   Membranous ligule   Grasslike Weeds
Barnyardgrass   Yellow foxtail       Star-of-Bethlehem
    Bristly foxtail       Yellow nutsedge
             

Weed ID Keys

Broadleaf and Grass and Grasslike Weed Vegetative Identification Keys
These keys describe 27 broadleaf and 20 grass or grasslike weed seedlings
found in corn and soybeans. They focus primarily on characteristics of
leaf arrangements, true leaves, grass ligules, and cotyledons. Sketches
are used to determine proper identification.
Z840.1 Two keys, 8p ............................................ (bundle of 25) $30.00

Weed ID keys are availible from ITCS group at UI.

Other Weed ID Keys

Web based weed identification key

Weeds of the North Central States

Early Spring Weeds of No-till Crop Production

A Pocket Identification Guide of Early-Season Weed Species

  The University of Illinois

College of Agricultural, Consumer and Environmental Sciences
Crop Sciences| University of Illinois
University of Illinois Extension

Department of Crop Sciences