Pier Luigi Nims
Placynthium is a still rather poorly known genus of c. 25 species, included in the family Placynthiaceae, with the highest diversity in temperate areas of the Northern Hemisphere. The monotypic genus Collolechia, previously distinguished on the basis of differences in ascospores, ascus apex and the leprose thallus, was analysed by Košuthová & al. (2016) with molecular and morphological data, showing that it is clearly nested within Placynthium. The genus was monographed by Gyelnik (1940) for Central Europe; the species of the Iberian Peninsula were treated by Burgaz (2010), those of the Alps and neighbouring territories by Czeika & Czeika (2007), who also provide a complete key. According to Nimis (2016), 14 species are known from Italy.


Burgaz A.R. 2010. Nuevos datos sobre el género Placynthium en la Península Ibérica. Bot. Complut., 34: 5-19.
Czeika H., Czeika G. 2007. Placynthium in den Alpen und Karpaten sowie in benachbarten Gebieten. Herzogia, 20: 29-51. Gyelnik V. 1940. Cyanophili, II. Lichinaceae, Heppiaceae, Pannariaceae. Borntraeger\Leipzig. 1-272 pp.
Košuthová A., Fernández-Brime S., Westberg M., Wedin M. 2016. Collolechia revisited and a re-assessment of ascus characteristics in Placynthiaceae (Peltigerales, Ascomycota). Lichenologist, 48, 1: 3-12.
Nimis P.L. 2016. The Lichens of Italy. A Second Annotated Catalogue. EUT, Trieste, 739 pp.