Aim The species–area relationship (SAR) and the small‐island effect (SIE) are of important ecological significance. However, few studies have focused on these topics in regard to bryophytes. We aimed to (1) determine whether SIEs and a SAR with two thresholds and three different processes of species addition exist for bryophytes across continental islands and (2) test whether the SIE threshold tends to be high for stenoecious species with a high sensitivity to habitats and for those with relatively high resource requirements and low dispersal abilities. Location The Zhoushan Archipelago, China. Taxon Bryophytes. Methods We obtained species number data for five bryophyte categories (total bryophytes, total mosses, acrocarpous mosses, pleurocarpous mosses and liverworts) from 66 continental islands of the archipelago and analysed the dataset using 24 SAR models. According to Akaike's information criterion, we identified models suitable for revealing SARs and detecting SIEs among the five bryophyte categories. Results The power model was best for fitting SARs of all bryophyte categories except for pleurocarpous mosses. For detecting SIEs, the three‐segmented model provided the best support for the five categories. There were obvious SIEs for the five bryophyte groups, with area thresholds of 0.11–1.42 km2. The SIE threshold was much higher in liverworts than in mosses and in pleurocarpous mosses than in acrocarpous mosses. The second thresholds for the five categories were similar, ranging from 53.62 to 73.19 km2. Main conclusions A unique SAR pattern with two area thresholds and three different dominant processes of species addition with island area was found for bryophytes across the continental islands. The second thresholds were not due to in situ speciation but were likely due to the high immigration of bryophytes from the mainland attributed to local residents. The SIE thresholds detected for the different categories of bryophytes indicated that the values tended to be low for species groups with low resource requirements and high dispersal abilities and high for those with a high sensitivity to habitat conditions, the latter indicating that areas for conservation purposes for species sensitive to habitats should be comparatively large.

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Summary Solidago canadensis is a noxious invasive species in China. We examined the influences of herbicides on pollen germination and pollen tube growth and the effects of cutting flowers and herbicides on seed production and quality. We also determined the seed production and resource allocation to different organs of S. canadensis after uprooting the plants during their reproductive periods. The main results were as follows: (i) 49% pollen of S. canadensis was able to germinate on an appropriate medium; (ii) compared with paraquat, ethephon and 2,4‐D, glyphosate had an ideal inhibitory effect on pollen germination and the formation of seeds of S. canadensis; (3) cut flowering branches, when placed in water or nutrient solution, were still able to produce viable seeds; (4) resources were allocated more to the inflorescences to facilitate seed maturation after plants were uprooted at the flowering stage. Uprooted flower branches were still able to produce viable seeds, especially those in full flower. Therefore, in order to reduce the seed production of S. canadensis and spread of the species we suggest: (i) apply glyphosate at the flower bud stage, (ii) completely destroy uprooted plants at flowering stages and (iii) avoid using the flowering branches as ornamental materials.

A total of 46 species and two varieties of the traditionally interpreted genus Orthotrichum are currently known to occur in China. They represent five genera, including Orthotrichum (29 species), Lewinskya (14 species and two varieties), and Nyholmiella and Leratia that are represented by a single species each. The fifth genus Florschuetziella, also consisting of only one species, F. scaberrima, is an entirely neglected representative of the China’s moss flora. A list of all accepted taxa is presented and for each taxon all literature records and herbarium specimens are enumerated for provinces in which they have been recorded, and their distribution is mapped. A key to determination of Chinese orthotrichalean mosses is presented. A chronological list of 63 species and varieties and two designations, O. catagonioides and O. microsporum which have never been validly published, reported from China in the years 1892–2020 is presented. Four species, Orthotrichum brasii, O. hooglandii, O. elegans and O. gymnostomum are excluded from the bryoflora of China and Lewinskya affinis var. bohemica and Orthotrichum schimperi are recorded for the first time from this country. Phytogeography of the Chinese taxa of the orthotrichalean mosses is considered and they are grouped into eight phytogeographical elements and five sub-elements.