Taxonomic Revision and Conservation Status of Bartramia (Bartramiaceae, Bryophyta) in China, with a New Record and an Updated Key.

The genus Bartramia, commonly known as "Apple Moss," is characterized by its globose to subglobose capsules. However, the species diversity and distribution of the genus in China remain incompletely known due to the lack of a comprehensive taxonomic revision. In this study, we conducted a taxonomic revision of this genus in China, based on recent field collections and herbarium specimens. In total, 120 specimens from twelve provinces in China were examined. Bartramia deciduifolia is newly reported for China, where it occurs in Qinghai, Sichuan, Xizang, and Yunnan. Seven species are recognized in China: B. brevifolia, B. deciduifolia, B. halleriana, B. ithyphylla, B. laevisphaera, B. pomiformis, and B. subulata. Among them, B. laevisphaera is proposed as an endangered [EN B2ab(ii, iii)] species due to its small population and habitat, while the other six species are Least Concern (LC). Detailed morphological descriptions, color illustrations, and distributional information are provided, together with an updated identification key to the Chinese species.