No abstract

Extraits d'éléments de la Figure 4 / Extracts of the Figure 4 201 CRYPTOGAMIE, BRYOLOGIE • 2022 • 43 (14) © Publications scientifiques du Muséum national d'Histoire naturelle, Paris.

Riccia is the largest genus of complex thalloid liverworts (Marchantiopsida) with over 250 species currently accepted. Our recent investigation of Chinese liverworts found two interesting Riccia species, R. junghuhniana and Riccia subcrinita sp. nov. Riccia junghuhniana is currently known from Australia and Indonesia, while Riccia subcrinita is known only from China. Riccia subcrinita is similar to R. crinita, but differs in having smaller spores (56–71 µm in diameter), and spore distal surface and proximal surface alveoli without thick borders. The sequences of rbcL, rps4, and trnL-F, detailed descriptions, and illustrations of the Chinese specimens are provided. The range extension of R. junghuhniana suggests that more taxa of Riccia may have a wider distribution. The discovery of R. junghuhniana and the new species also suggests that a more intensive survey of Riccia diversity in China is necessary.

Dicranum is one of the most diverse and widespread genera within the Dicranaceae. Species diversity and distribution in this genus, however, remain not well known. During our recent expeditions to the Hengduan Mountains in China, we found an interesting moss referrable to Dicranum species that is characterized by the stiff and fragile leaves, bistratose alar cells, and by the costal cross-section in the lower portion without stereid bands with one layer of cells above and below guide cells. Morphological and molecular-phylogenetic analyses based on five chloroplast markers (rpoB, rps4-trnT, rps19-rpl2, trnH-psbA, and trnL-trnF) and one nuclear marker (ITS region) suggest that this unknown moss represents a new species here described as D. hengduanensis. The plastome of this new species presented in this study is the first complete plastome of Dicranum.

Xiang, Y.-L., Xu, H., Shen, C., Huang, W.-Z., Zhang, L.-N., Shu, L. & Zhu, R.-L. 2023. Taxonomic notes and range extension of several complex thalloid liverworts. – Herzogia 36: 193 –205.Riccia billardierei Mont. & Nees and R. rhenana Lorb. ex Müll.Frib. were found in Southern China. Phylogenetic analyses of the genus Riccia based on the sequences of rbcL, rps4, and trnL–F reveal that two Chinese samples of R. billardierei and six samples from Australia and Thailand form a well-supported clade, which is sister to R. gangetica. Riccia rhenana is molecular-phylogenetically investigated for the first time and it is sister to R. fluitans L. Sphaerocarpos siguniangensis R.L.Zhu & You L.Xiang was discovered for the first time outside the type locality. The Chinese Exormotheca bischlerae Furuki & Higuchi, previously known only from Sichuan, was newly found in Yunnan and Xizang. In addition, Aitchisoniella himalayensis Kashyap and Peltolepis quadrata (Saut.) Müll. Frib. rare in China were found for the first time in Yunnan and the Qinghai-Tibet Plateau, respectively. Illustrations of Aitchisoniella himalayensis, Exormotheca bischlerae, Peltolepis quadrata, Riccia billardierei, R. rhenana, and Sphaerocarpos siguniangensis are provided.