Leaves arise from bulb - wild onion, wild garlic or Star-of-Bethlehem

Stems triangular - yellow nutsedge

Leaves form sheath at stem, blue-purple flowers - dayflower

Ligule absent - barnyardgrass

Ligule membranous

    Blade or sheath with dense hairs

        >First leaf wide and short, decumbent growth habit - large crabgrass

        >Leaf blades distinctly twisted, winter annual - downy brome

    Blade and sheath hairless or sparsely hairy

        >Blades wide, short

            >>Sparse hairs near collar, decumbent growth habit - smooth crabgrass

            >>Prominent veins, sheath flat with whitish base - goosegrass

        >Blades narrow and erect

            >>Auricles present, smooth white rhizomes - quackgrass

            >>Auricles absent

                >>>Winter annual, forms clumps, blade tips prow-shaped - annual bluegrass

                >>>Perennial with rhizomes, seed oblong-shaped - johnsongrass

                >>>Summer annual, resembles johnsongrass but has no rhizomes, large shiny black ovate seed - shattercane

Ligule hairy

    Blade with hair

        >Short hair on upper surface - giant foxtail

        >Long hair on upper leaf surface near base of blade - yellow foxtail

        >Blades and sheath covered with dense short hair, sheath hair at 90 degree angle to stem - witchgrass

        >Very short dense hair on blades, first leaf horizontal, blade margin often crimped, large seed - woolly cupgrass

   Blade with little or no hair

        >Sheath margin hairy - green foxtail

        >Sheath margin usually hairless or with a few hairs

            >>Perennial, rhizomes and stolons present, roots at nodes, decumbent growth habit - bermudagrass

            >>Sheath round, hair on underside of first leaf, later leaves smooth, prominent white midvein - fall panicum

            >>Sheath flattened, usually reddish in color, large spiny seed - field sandbur