Phytotaxa 306 (1): 001–020 ISSN 1179-3155 (print edition) http://www.mapress.com/j/pt/ PHYTOTAXA Copyright © 2017 Magnolia Press Article ISSN 1179-3163 (online edition) https://doi.org/10.11646/phytotaxa.306.1.1 A taxonomic revision of cleistocarpous species of Weissia (Pottiaceae, Bryophyta) in Japan YUYA INOUE1, 2, 4 & HIROMI TSUBOTA3 1Department of Biological Science, Graduate School of Science, Hiroshima University, 1–3–1 Kagamiyama, Higashi-hiroshima-shi, Hiroshima 739–8526, Japan. 2Hattori Botanical Laboratory, 6–1–26 Obi, Nichinan-shi, Miyazaki 889–2535, Japan . 3Miyajima Natural Botanical Garden, Graduate School of Science, Hiroshima University, 1156–2 Mitsumaruko-yama, Miyajima-cho, Hatsukaichi-shi, Hiroshima 739–0543, Japan. 4Author for correspondence (
[email protected]) Abstract Four species, including one newly described, of Japanese cleistocarpous species of Weissia (Pottiaceae): W. exserta, W. japonica, W. kiiensis and W. parajaponica sp. nov. are recognized based on molecular phylogenetic inference and morpho- logical reassessment. For each species, typification, description, distribution, illustrations and photographs are presented, and a key to the species is included. Rapid sporophyte modifications in Weissia and monophyletic positions of these four species are supported by the analysis using concatenated chloroplast rbcL and rps4 gene sequences. A lectotype is designated for W. controversa which is the type species of the genus, and a new combination, W. loncophylla is proposed for Trachy- carpidium lonchophyllum. Key words: Gametophyte, Sporophyte, Stegocarpous Introduction Among bryophytes, mosses show the most complex and diverse sporophytes. Sporophyte diversification can be explained in relation to their habitat preferences, and an understanding of sporophyte modification will help to clarify ideas of evolutionary parallelisms and adaptive specialization in mosses (Vitt 1981).