Rhizocarpon macrosporum (lemon map lichen) is a smooth, bright yellow crustose aereolate lichen found in the Sonoran Desert of California and Arizona, and in Africa and Asia.

[1] It grows on non-calciferous rock in clearings in coniferous forests, from 1,475 to 3,030 metres (4,839 to 9,941 ft).

[1] It is very similar to R. geographicum except for the size of the spores.

[1] "Macrosporum" means "large spore".

Areoles are 1.4 to 2 millimetres (0.055 to 0.079 in) in diameter and round to angular.