Canoparmelia texana
Canoparmelia texana photo by Ray Showman
DIAGNOSTIC FEATURES: Light, almost white color, powdery soredia, medulla K-; compare with C. crozalsiana which has patterned ridging and medulla K+ yellow, and with Myelochroa aurulenta which has a smaller size, yellowish medulla, medulla K+ yellow.
ECOLOGY: Rather rare in the southeastern US; found in seven southern Ohio counties, where it prefers hard-barked oaks (chestnut oak plus black oak group) on dry ridgetops.