Schistochila gradsteinii sp. nov., a new species from New Caledonia related to S. vitreocincta (Schistochilaceae, Marchantiophyta), with a key to the local species and a description of the gynoecium of S. integerrima

Schistochila gradsteinii Thouvenot sp. nov., is added to the five Schistochila Dumort. species formerly known in New Caledonia. The new species is distinctive by the lack of underleaves, bilobed leaves entire margined, with larger ventral lobes oblong-lanceolate to oblong-ovate, apiculate, dorsal lobes oblong-ovate, inserted on the dorsal surface of ventral lobes, the free margins not reaching the ventral margins, leaf cells with seemingly 3-layered trigones, stems with a conspicuous epidermis. It shares with the endemic S. vitreocincta (Herzog) X.L.He & Glenny some features distinctive from the rest of the genus. In addition, the occurrence of S. vitreocincta is clarified, the gynoecium of S. integerrima Steph. is newly described and a key to the New Caledonian species of Schistochila is provided.