Psilocarphus brevissimus is a species of flowering plant in the family Asteraceae known by the common names short woollyheads, woolly marbles, and woolly heads.

It grows in moist flats such as vernal pools, wetlands, and similar areas.

The small, gray-green leaves are erect, pointing up parallel to the stem and sometimes appressed to it.

The inflorescence is a small, spherical flower head which is a cluster of several tiny woolly disc flowers surrounded by leaflike bracts but no phyllaries.

Each tiny flower is covered in a scale which is densely woolly with long white fibers, making the developing head appear cottony.