Xanthoparmelia ajoensis is a foliose lichen that belongs to the genus Xanthoparmelia. The lichen is uncommon and is listed as vulnerable by the Nature Conservatory.
Xanthoparmelia ajoensis grows to around 2âÂÂ6 cm in diameter with irregularly lobate lobes which are approximately 1âÂÂ3 mm wide. The upper surface of the lichen is yellow-green with cylindrical isidia. The lower surface is pale brown to brown. Xanthoparmelia ajoensis is a member of the Xanthoparmelia mexicana group, a complex of similar species that differ mainly in their secondary chemistry.
Xanthoparmelia ajoensis is found in the North American southwest including the US states of Arizona, California, Colorado, and New Mexico and the Mexican states of Sinaloa and Sonora.
Xanthoparmelia ajoensis has been recorded as containing usnic acid, 3-ñ-hydroxybarbatic acid, and diffractaic acid.