** Plectocolea vulcanicola f. cavifolia (Schiffn.) Bakalin,

Arctoa 23: 125, 2014, nom. inval. ICN Art. 41.1; basionym not valid (see Bakalin 2014a). BASIONYM: Nardia vulcanicola f. cavifolia Schiffn., Denkschr. Kaiserl. Akad. Wiss., Math.-Naturwiss. Kl. 67: 192, 1898, nom. inval. ICN Art. 38.1(a); no description (see Schiffner 1898).