Old eastern North American records of Lobaria/Ricasolia amplissima are thought to refer to Ricasolia quercizans (Michaux) Stizenb. See Hale 1957; Cornejo et al. 2017. A quick spot test will confirm: the medulla of R. quercizans should be strongly C+ red, while R. amplissima is C-. Thank you! Hale, M.E., Jr. 1957. The Lobaria amplissima-L. quercizans complex in Europe and North America. The Bryologist 60(1): 35–39. Cornejo, C., C. Derr & K. Dillman. 2017. Ricasolia amplissima (Lobariaceae): one species, three genotypes and a new taxon from south-eastern Alaska. The Lichenologist 49(6): 579–596.