Tomnashia luteominia, the red firedot lichen, is a species of saxicolous (rock-dwelling), crustose lichen in the family Teloschistaceae. It is widely distributed along the North American west coast. The lichen has two varieties: var. bolanderi has distinctive red apothecia (fruiting bodies), while var. luteominia has orange-brown apothecia.
The lichen was first formally described as a new species in 1866 by the American lichenologist Edward Tuckerman, as Placodium luteominimum. Sergey Kondratyuk and Jae-Seoun Hur transferred it to the genus Tomnashia in 2017. It is commonly known as the "red firedot lichen".