This is an annual growing to 2 feet tall.
It spreads by seed.
Leaves are 2 to 5 inches long, deeply lobed, and have prominent veins.
Flowers are yellow, 5-lobed, and about 1 inch wide.
Stems and seed capsules are covered with spines.
Buffalobur is a native to the West, but can become a nuisance on disturbed sites such as roadsides, ditchbanks, and overgrazed pastures. It is very drought resistant. This plant is frequently found in the north west areas of Natrona County along roadsides.
Chemicals must be applied before seed production. Seeds may germinate more than once a season. Call your local weed district for more info.