Name: Cystoderma fallax
Author: A.H. Sm. & Singer
Citation: Pap. Mich. Acad. Sci. 30: 116 (1945) 1944
Preferred Synonyms:Cystoderma carcharias var. fallax (A.H. Smith & Singer) I. Saar
Don’t use MB/IF to change preferences on MO.
They are excellent (necessary) resources for which names exist, but synonym preference is a secondary function (at best) on both sites. You need to cite literature.
C. fallax was relegated to a variety of C. charcharias by Saar in 2012 (https://www.researchgate.net/publication/316879669) on the basis of ITS data.