Trichoptilium is a monotypic genus containing the single species Trichoptilium incisum, which is known by the common names yellowdome and yellowhead. This is a plant in the daisy family which is native to the Mojave and Sonoran Deserts of the United States and Mexico.
T. incisum sends up stems from a basal rosette of sharply-toothed leaves which are covered in curly hairs and oil glands. Atop each stem is a small rounded bright yellow flower head with only disc florets. Each head is a hemispherical button about a centimeter in diameter. The fruit is bristly with pappus.