Didiclis pseudobisulcata (Selaginellaceae), a new species of the Bisulcata group from northern Thailand and southwest China

Didiclis pseudobisulcata (Lycopodioidoideae, Selaginellaceae), a new lycophyte species from northern Thailand and southwest China, is described and illustrated. Morphologically, it is similar to D. bisulcata but can be reliably distinguished by its dorsal leaves on branches with an arista often more than 3/4 of the leaf length, the densely ciliolate base of the dorsal sporophyll pteryx, and megaspores with subreticulate exospore ornamentation. Molecular phylogenetic analysis based on ITS and rbcL sequences supports this species as an independent clade. The ITS sequences revealed more than 42 nucleotide differences between the new species and other members of the Bisulcata group, providing clear molecular evidence for its separation from its closest relatives.