Protoharpanthus gen. nov. (Harpanthaceae) - a relict relative of Harpanthus from the Sino-Himalaya

摘要

The new genus Protoharpanthus is described from the Salween River Basin in the Hengduan Mountains, Sino-Himalaya. The genus superficially resembles Lophocolea or slightly even Calypogeia, but phylogenetically is quite far from both and belongs to the oligotypic Harpanthaceae. The new genus is a shining example of parallelism in the evolution of liverworts and is characterized by succubous and shortly bilobed leaves with a differentiated margin of elongate cells, finely verruculose leaf cuticle, distinct stem hyalodermis with large trigones in the outer cells of the stem cross section, bilobed underleaves, rhizoids restricted to underleaf bases and exclusively ventral intercalary branching. In both phylogenetic and phytogeographical senses this genus is a relict in the Sino-Himalayan bryoflora.