Types

• Common crabgrass types are: hairy (Digitaria sanguinalis); fall witchgrass (Digitaria cognata); fonio (Digitaria exilis); sourgrass (Digitaria insularis); smooth (Digitaria ischaemum).
  
  

Form

• Crabgrass appears more like a plant, with multiple stems and leaves. A crabgrass plant has a main stem, from which smaller stems grow out between 45 and 90 degrees. These smaller stems will also have their own stems. An individual crabgrass can grow to a height between 1 and 4 feet, and the width between 8 inches and 2 feet. Stems range from light green to dark green in color.
  
  

Flowers

• Crabgrass plants have flowers, which are composed of small node-like heads. These flower heads can grow on the end of stems, or can be clustered along the length of a stem. For flower heads that are clustered along the stem, these can be directly attached to the stem, or can have their own small stem. Flower heads are often a lighter green in color.
  
  

Seeds

• The flower heads eventually turn into seeds. Seeds are long, oval shaped, and have small and coarse hairs along their body. A seed is light brown to brown in color, and the tip often is light purple to purple. Ridges often run along the length of a seed.
  
  

Location

• The hairy crabgrass species can be found throughout the United States, excluding Florida, Hawaii and Alaska as of 2010. In Canada, this species is found in every southern province. The fall witchgrass is found east from a line extending from Texas, excluding the Dakotas and including Ontario. Sourgrass grows in Hawaii, Arizona, Texas, Illinois, Mississippi, Alabama and Florida. The smooth variety can be found in all states, excluding Hawaii and Alaska, and in the southern provinces of Canada.
  
  

Species Distinction

• The flower heads of the hairy variety do not have their own stem, and grow along the length of the stem. The flowers of the fall witchgrass variety grow on stem tips. The fonio species' seeds are less elongated than others and resemble an unsheathed almond. The sourgrass variety produces flowers that have their own stems, which also grow along the stem length, to give the appearance of a wheat plant.