Holocarpha virgata is a species of flowering plant in the aster family known by the common name yellowflower tarweed. It is endemic to California, where it is most common in the Central Valley and adjacent foothills to the east and west. There is also a disjunct population near San Diego. This is an annual herb producing an erect stem 20 centimeters to over one meter tall. It has many branches and is lined with oily glands and hairs. The linear leaves are up to 15 centimeters long near the base of the plant and those along the stem are much smaller. The flower cluster is made up of several short branches lined densely in small, thick, green leafs. The leafs are just a few millimeters long and are tipped with glands. At the ends of the branches are flower heads, each lined with phyllaries which are covered in knobby resin glands. The head contains many disc florets which are yellow with black or purplish anthers. The head has a fringe of several yellow ray florets which often have lobed tips.