Two new species of the Lycophyte Genus Selaginella (Selaginellaceae) from China, with notes on phylogenetic position of related species

Two new species of lycophytes, Selaginella obovata and S. zhangii, were
discovered in southeastern Yunnan, China. Selaginella obovata is
characterized by the prostrate habit and relatively small size of plant,
obovate median leaves, and short, dorsiventral strobili, and is not
apparently similar to any known species. Phylogenetic analyses of plastid
sequences (rbcL, atpI, psbA) indicated that S. obovata is closely allied
to S. bisulcata, which is also supported by spore morphology, and that
these two taxa together with S. pennata constitute a well-supported
monophyletic group. Selaginella zhangii is comparable to S.
rolandi-principis in their broad stems (including leaves) and shape and
arrangement of vegetative leaves; but the former differs from the latter
in its prostrate habit and dorsiventral strobili. The result of
phylogenetic analyses showed indicate that S. zhangii is allied to S.
heterostachys in the S. heterostachys–S. ciliaris clade, while S.
rolandi-principis is distantly placed in the S. doederleinii–S. involvens
clade. Finally, we provide comprehensive descriptions, photographs of
living plants, line drawings, and scanning electron micrographs of spores
to facilitate their recognition.