Cladonia ciliata var. tenuis
Cladonia sylvatica auct. p.p.
Cladonia tenuis
The usnic acid containing morph of Cladonia ciliata, has been separated at varietal or form level (Cladonia ciliata var. tenuis (Flörke) Ahti (1993) or C. ciliata f. flavicans (Flörke) Ahti & DePriest (2001)) and there are some ecological and distributional differences. The morphs, however, grade into each other with intermediates found with low concentrations of usnic acid, and C. ciliata is treated as a single polymorphic taxon by Pino-Bodas et al (2012). See Cladonia ciliata for more details of this species.
For the time being this morph is still being recorded separately in the BLS database.
Pino-Bodas, R., Sanderson, N., Cannon, P., Aptroot, A., Coppins, B., Orange, A. & Simkin, J. (2021). Lecanorales: Cladoniaceae, including the genera Cladonia, Pilophorus and Pycnothelia. Revisions of British and Irish Lichens 19: 1-45. Link
Text by Neil A Sanderson based on Pino-Bodas et al (2021)