A classification of Selaginella (Selaginellaceae) based on molecular (chloroplast and nuclear), macromorphological, and spore features

Abstract The largest genus of seed‐free vascular plants Selaginella alone constitutes t he family Selaginellaceae, the largest of the lycophyte families. The genus is estimated to contain ca. 800 species distributed on all continents except Antarctica, with the highest species diversity in tropical and subtropical regions. The monophyly of Selaginella has rarely been doubted, in contrast its infrageneric classification has been contentious. In the present study, based on chloroplast and nuclear DNA evidence, macromorphology, spore features, and/or distribution information, Selaginella is classified into six subgenera: S . subg. Selaginella , S . subg. Boreoselaginella , S . subg. Pulviniella , S . subg. Ericetorum , S . subg. Heterostachys , and S . subg. Stachygynandrum . The latter three subgenera are further classified into six, five, and seven sections, respectively. All of these infrageneric divisions, identified with molecular data, are supported by non‐molecular features. A key to infrageneric taxa is given. Thirty‐seven infrageneric taxa published in earlier literature are lectotypified and classified into those infrageneric taxa here recognized. A nomenclatural account of each infrageneric taxon is given.