Smith, G. F., and N. R. Crouch. “A Review of the Nomenclature and Identity of Cotyledon mucronata and C. undulata (Crassulaceae Subfam. Cotyledonoideae), Two Names Variously Applied to Undulate Leaf-Margined Material Generally Included in the Synonymy of Different Varieties of C. orbiculata, With C. mucronata Reinstated at the Rank of Species”. Phytotaxa, vol. 714, no. 1, Aug. 2025, pp. 40-56, doi:10.11646/phytotaxa.714.1.2.