ABSTRACT Introduction. Macromitrium giraldii Müll.Hal. was previously considered a synonym of M. japonicum Dozy & Molk. Our ongoing research on the genus Macromitrium Brid. has enabled us to identify morphological differences between M. japonicum and M. giraldii, as well as a close similarity between the latter and the widely distributed East Asian M. cavaleriei Cardot & Thér. Here we present morphological and phylogenetic evidence supporting our speculation that M. giraldii and M. cavarleriei are conspecific, and that the former should be recognised. Methods. A morphological study of the original material of Macromitrium giraldii, M. cavaleriei, M. japonicum and their accepted synonyms was conducted, including recent specimens matching their descriptions. A phylogenetic analysis based on the nuclear ITS2 and the plastid trnL–F and trnG regions was performed to investigate relationships within the genus. Key results and conclusions. The morphological and phylogenetic data support Macromitrium giraldii and M. cavaleriei as conspecific, with similarities observed in their branch leaves. All previously accepted synonyms of the latter are additionally confirmed to be M. giraldii. We here propose to synonymise these two species as M. giraldii, since this name has priority. Consequently, M. giraldii is distributed throughout China, as well as in Japan, South Korea, Vietnam, Nepal and India.

ABSTRACT Introduction Light has long been assumed to be required for the successful germination of bryophyte tubers. We tested this assumption for Timmiella crassinervis by assessing tuber germination under light and dark conditions, longevity in darkness, and the ability to surface from burial depths of up to 9 mm of sand. Methods Cultured tubers of Timmiella crassinervis were placed in darkness for durations of up to a year (dark-longevity experiment), or buried at sand depths of up to 9 mm (burial experiment). In the dark-longevity experiment, viability and vigour were assessed by observing the presence and number of stolons produced during darkness, the first day of germination on exposure to light (regermination), the number of days to production of the first shoot, and the total number of shoots produced after 30 days in light. In the burial experiment, the timing of surfacing and the ability to form colonies in culture were assessed. Key results and conclusions When placed in total darkness, tubers of Timmiella respond by producing gravitropic and lateral rhizoidal stolons. Tubers can survive for at least 12 months in a hydrated condition in darkness after dark germination. Buried tubers were able to reach the media surface from a depth of 9 mm of sand sieved to < 355 μm. Regermination is defined as dark germination through stolons, followed by light germination through protonemata. The dark germination in this species may be an adaptation to challenges of frequent wildfires and flooding in its native habitat of California.

ABSTRACT Introduction Bryophytes often grow in habitats where they are subjected to multiple abiotic stresses, for example high or low light, temperature extremes and desiccation. When plants absorb more light than they can use for photosynthesis, non-photochemical quenching (NPQ) can dissipate excess light energy as heat, thus reducing damage to the photosynthetic apparatus. Light stress is likely to be more harmful at lower temperatures, because while rates of photophosphorylation are almost temperature-independent, low temperatures will decrease carbon fixation, which is dependent on enzyme activity. We tested the effect of an exposure to moderate light stress in combination with chilling stress on NPQ in four bryophyte species. Methods We used chlorophyll fluorescence to study how levels of NPQ, measured at room temperature, are affected by the effects of a combination of short-term moderate light stress (200 μmol m−2 s−1) and chilling to 5°C. Four species of bryophytes were used: first, the relatively stress-sensitive moss Atrichum androgynum; second, the more tolerant moss Dicranella subsubulata; third, the liverwort Marchantia polymorpha; and fourth, the hornwort Anthoceros natalensis. Key results Our results showed that, while all species suffered only slight photoinhibition, the mosses, but not the liverwort or hornwort, respond to the stresses by rapidly increasing NPQ. However, for all species the effect of light on NPQ was similar at both 15°C and 5°C. Conclusions While for some bryophytes, particularly mosses, NPQ can rapidly increase in response to moderate light stress, additional photoprotective mechanisms are likely to be involved when light and chilling stress co-occur.

ABSTRACT Introduction Taxiphyllum barbieri (Cardot & Copp.) Z.Iwats (Java moss) has significant commercial and scientific applications, and optimising its growth is crucial for maximising benefits. The aim of the present study was to investigate key factors influencing the growth of T. barbieri, including nutrient type, nutrient concentration (NC), photoperiod, and levels of dissolved inorganic carbon (DIC). Methods We used response surface methodology (RSM) and Design-Expert software to analyse the complex interactions between these factors and both moss development and chlorophyll and carotenoid production. Key results Maximum growth and pigment production were observed when the NPK (nitrogen, phosphorus, potassium) nutrient medium was used. Optimal conditions for NPK, yielding the maximum relative growth rate (23.8 mg × g−1 d−1), were NC, 82.86%; photoperiod, 6.40 h; and DIC concentration, 0.278 μM. For optimal pigment production in NPK (total chlorophyll and carotenoid content of 2.93 mg × g−1 and 0.199 mg × g−1, respectively), the conditions were NC, 74.29%; photoperiod, 6 h; and DIC concentration, 0.10 μM. These results suggest that higher NC and lower DIC concentration are favourable conditions for pigment production in the NPK medium. The resilience of T. barbieri to increased nutrient levels was also assessed. Conclusions In the study, the growth parameters for Taxiphyllum barbieri were optimised using the RSM approach. Our findings provide insights into factors influencing moss development, particularly the critical role of NC, photoperiod and DIC in promoting optimal growth and pigment production. This knowledge could inform strategies for enhancing moss cultivation and water pollution mitigation.