Hymenasplenium inthanonense (Aspleniaceae), A New Fern Species from Doi Inthanon, and its Phylogenetic Status

Abstract

A new species of Aspleniaceae, Hymenasplenium inthanonense N. Murak. et J. Yokoy. was described from Doi Inthanon, Tha iland . This species is closely re lated to H. cheilosorum, but can be distinguished by it more medial sorus position and less dimidiate pinnae. It is readily recognizable even in mixed populations by its morphological, cytological, ecological and molecular characters. The relatively large (about 10 base pairs) difference in the s lowly evolving rbcL gene between H. inthanonense and H. cheilosorum indicated that they d ifferentiated into two different biological species long ago.