Ambrosia acanthicarpa is a North American species of bristly annual plants in the family Asteraceae.

The plant is common across much of the western United States and in the Prairie Provinces of Canada.

[5][6] This spiny, weedy plant grows in clumps of many erect stems which may reach over a meter in height.

Its gray-green stems are covered in a coat of stiff, bristly hairs.

The species is adaptable and grows well in disturbed areas, easily becoming weedy.