Development and survival of Buxbaumia viridis (Moug. ex DC.) Brid. ex Moug. & Nestl. sporophytes in Hungary

ABSTRACT Introduction Buxbaumia viridis is a rare but well-researched bryophyte in Europe. Owing to its small size and unusual life cycle, its developmental stage is key for its detection in the field, so it is surprising that intensive field research on its phenology has not previously been carried out. Methods During a systematic study from 2014 to 2020, data from extensive (space-for-time) and intensive surveys were collected on the development of Buxbaumia viridis sporophytes in Hungary. Damage to sporophytes and sporophyte survival rate were also examined. Key results Twelve developmental stages were distinguished and characterised in this study. Juvenile sporophytes started to grow in autumn, and about half of the sporophytes died before their maturation in summer. Asexual propagules (gemmae) were produced all year round. Conclusions Precise description of the developmental characteristics helps distinguish Buxbaumia viridis from B. aphylla, even at juvenile stages in autumn; however, early spring was found to be the best period for field surveys. The observed mortality rate is probably a species-specific constant, so (on its own) may not pose a threat to the survival of populations. Large numbers of gemmae probably increase the likelihood of local survival.