Buffalobur

Foliage.  Key characteristics: leaves are alternately arranged with irregularly lobed margins.  Veins have dense, straight hairs.

Stems.  Note the stiff spines.

Fruit.  Armed with stiff, yellow spines.

Habitat.  Buffalobur is primarily a weed of pastures in Missouri.

Seed.  Seed have a wrinkled texture, nearly black in color and the length is approximately 2.0 to 3.0 mm.

Life cycle: summer annual.