Umbilicaria nodulospora is a species of foliose lichen in the family Umbilicariaceae,[1] discovered on steep rock faces of old lava flows in California and Oregon, USA.

The species was formally described in 2014 by Bruce McCune, Joseph Di Meglio, and Marc J. Curtis, following DNA analysis and detailed study of its unique spore morphology.

The molecular phylogenetics analysis involved the internal transcribed spacer (ITS) and large subunit (LSU) of ribosomal DNA, confirming its distinctiveness but not identifying any close relatives within the Umbilicariaceae.

[2] The thallus of Umbilicaria nodulospora is either monophyllous (single-leafed) or polyphyllous (multiple leaves), growing up to 2–3 cm (0.8–1.2 in) in diameter and about 0.2 mm thick, excluding the rhizines.

It features a brown to gray-brown upper surface that is faintly to distinctly pruinose (powdery), creating a grayish effect especially near the central attachment point (umbo).