B. ‘Sanguinea × Vulcanicola’, though evidently intended merely as a hybrid formula, was arguably published in the form of a cultivar name in Kirchner-Abel et al. (2004: 66), where it appears as an epithet in single quotes though with no capitals. It cannot be established as it includes a mathematical symbol and thus contravenes Art. 21.19 of the 2009 ICNCP.