C. giganteus may refer to: Chorus giganteus, a sea snail species Cordylus giganteus, the giant girdled lizard, a lizard species Cryptanthus giganteus, a plant species endemic to Brazil Cynosurus giganteus, a grass species in the genus Cynosurus Cyperus giganteus, the piripiri, a plant species native to central Mexico as far south as Uruguay
Synonyms Cereus giganteus, a synonym for Carnegiea gigantea, the saguaro, a cactus species native to the U.S. states of Arizona and California and to the Mexican state of Sonora Crotalus giganteus, a synonym for Crotalus adamanteus, a venomous pitviper species found in the southeastern United States