Studies in the genus Riccia (Marchantiales) from southern Africa. 23. R. bullosa: typification and a full description

Abstract

In the protologue of Riccia bullosa, Lindenberg (1829) based his vague and incomplete description of the taxon on two heterogeneous elements: a specimen from Portugal and one from the Cape. Stephani (1898) retained the name Riccia bullosa for the Cape element and referred the Portuguese plant to  Exormotheca welwitschii (Stephani 1899). Although generally accepted until 1940. K. Muller (1940) rejected Stephani's segregation and referred the Portuguese element to his new combination. Exormotheca bullosa (Link) K. Muller, based on the false assumptions that Stephani had failed to recognize that the Portuguese plant was an Exormotheca. and that the Cape plant was insufficiently known and had not been found again. Counter arguments are set out here, urging a return to Stephani’s earlier segregation. A lectotvpe for Riccia bullosa is selected, which results in the repudiation of Müller's (and Grolle's) lectotypification of Exormotheca bullosa  (=Riccia bullosa).