The annual herb of the mint family Trichostema lanceolatum is commonly known as vinegar weed because its foliage contains volatile oils that have a strong vinegar odor. Other common names for the plant include terpentine weed and camphor weed. The oils also have phytotoxic properties, which help vinegar weed compete by killing or injuring other plant species. Indians of northern California used the plant as a cold and fever remedy, a pain reliever, and a flea repellent. Vinegar weed is a wildflower bearing striking purple-blue flowers on short green stems. The numerous leaves are juicy and green and are covered in fluffy hairs. The plant is well adapted to its native range in California, where it thrives in dry, nutrient-poor, sun-baked clay soil. In hot weather the vinegar smell of the plant becomes intense as the oils in the tissues permeate the air. The plants of this genus are sometimes called blue curls, but this name may be more associated with the similar, but sweeter smelling, species Trichostema lanatum. Vinegar weed is found on the west coast of North America from northern Mexico to southern Canada.