This is a key to all species of Farnoldia and Melanolecia known to occur in Italy (Nimis 2016), for a total of 10 infrageneric taxa.
The genus Melanolecia, as originally delimited, proved to be heterogeneous: the species with an amyloid ascus tip approaching the Porpidia-type were segregated into the genus Farnoldia, leaving a single species in Melanolecia s.str..
Farnoldia differs from Porpidia in the black exciple, which is usually separable from the hypothecium, from Schaereria and Tremolecia in the sessile apothecia, the ascospores with a thick perispore, and the amyloid tholus of the asci. A phylogenetic analysis based on molecular data suggests that the genus is most closely related to a group of genera (including Bryobilimbia, Clauzadea, Lecidoma and Romjularia) that do not belong to Lecideaceae s.str. (Fryday & al. 2014). All of the 6 hitherto recognised species are more or less calcicolous and have a more or less arctic-alpine distribution. The saxicolous species were treated by Hertel (1967, 1975).

References

Fryday A., Printzen Ch., Ekman S. 2014. Bryobilimbia, a new generic name for Lecidea hypnorum and closely related species. Lichenologist, 46, 1: 25-37.
Hertel H. 1967. Revision einiger calciphiler Formenkreise der Flechtengattung Lecidea. Beih. Nova Hedwigia, 24: 1-155.
Hertel H. 1975. Ein vorlaufiger Bestimmungsschussel fur die kryptothallinen, schwartzfruchtigen, saxicolen Arten der Sammelgattung Lecidea (Lichenes) in der Holarktis. Decheniana, 127: 37-78.
Nimis P.L. 2016. The lichens of Italy. A second annotated catalogue. EUT, Trieste, 740 pp.

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