Verrucariaceae Verrucaria nigrescens f. tectorum Growth type crustose Chemical results negative Found in the same habitats as Verrucaria nigrescens f. nigrescens, probably widespread but very under-recorded Differs from Verrucaria nigrescens f. nigrescens by the presence of green or olive-green blastidia that develop on the surface of the aureoles. The two forms are frequently found together

Verrucaria nigrescens f. tectorum
Steeple and Wareham, Dorset. February 2014, December 2016