To understand environmental influences of the accident of Fukushima Daiichi Nuclear Power Plant (FDNPP) and to elucidate a possibility of bryophytes as bioindicators for radioactivity deposition, a detailed analyses using a moss, Hyophila propagulifera were conducted. The sampling was done in the northeast part of Fukushima Prefecture on November 2014, three years after the accident. The sampling sites distribute at the three different distance ranges from FDNPP, remote (40–50 km), middle (25–40 km) and close (10–25 km). Forty-five samples were collected and analyzed the concentration (kBq/kg) of ¹³⁴Cs and ¹³⁷Cs in relation to the air radiation dose rate, distance from FDNPP, altitude, and slope angle. The analyses revealed a significant relationship between air dose rate (μSv/h) and radiocesium concentration in the moss (r = 0.87, p < 0.001, Pearson's rank correlation coefficient). The result suggests that H. propagulifera is a potential bioindicator for evaluation of radiocesium deposition in the environment. The maximum radiocesium concentration was detected from the plants collected in the Futaba area within 10–25 km range of FDNPP. Although the lowest radiocesium concentration was detected within middle distance range, the radiocesium concentration basically decreased depending on increase of a distance from FDNPP. As the changes of distance rages, a statistically significant correlation was observed between the radiocesium concentration and the altitude of the site. No obvious correlation was found between the radiocesium concentration and the slope angle of the sampling site.

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Morphological descriptions and taxonomic discussion of a liverwort species from New Zealand, Trichocolea elegans Colenso, are provided, with illustrations based on the lectotype newly designated in the present study. T. elegans Colenso is similar to Trichocolea hatcheri E.A.Hodgs. in having (1) small-sized plants of 0.8–1.2 cm wide including branches, (2) leaf discs 2–3 cells high bearing superficial cilia on marginal parts on the abaxial face, (3) dilated septa of leaf cilia, and (4) evenly thickened walls at the distal ends of terminal cells of cilia, and these species are indistinguishable from each other. In accordance with Hodgson’s treatment, T. elegans Colenso should be treated as a synonym of T. hatcheri.

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A re-examination of Japanese specimens previously identified as Encalypta vulgaris revealed that they are misidentified Encalypta rhaptocarpa. We were not able to confirm critical morphological characters (e.g., peristome and hair-pointed leaves) due to poor preservation of the plants, and in the present study we tried to determine the identity of the Japanese plants on the basis of spore morphology using scanning electron microscopy (SEM). The spores of the Japanese plants of E. vulgaris correspond to those of Encalypta rhaptocarpa, suggesting that E. vulgaris should be excluded from the Japanese flora.

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The family Pottiaceae is the most generic and species rich family in Bryophyta. The classification of this family is very difficult and controversial due to parallel or convergent evolution and sterility. In this paper, we briefly review the current state of knowledge on phylogeny and classification of the family. Molecular phylogenetic inference based on a new approach using a codon substitution model is also undertaken and confirm four clades within the Pottiaceae, corresponding to Trichostomoideae, Pottioideae, Merceyoideae, and a newly proposed subfamily Streblotrichoideae.

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We observed the development of archegoniophore in Marchantia polymorpha with a focus on the position and geometric orientation of archegonia. Our observations showed that the archegonia initially appeared on the underside of young archegonial receptacle in a hanging posture with their neck downward. However, some old textbooks have described that the archegonia of M. polymorpha initially arise on the dorsal side of young archegonial receptacle with their necks upward. Although the appearance of archegonia on the dorsal side of young archegoniophore has been observed in some other genera of Marchantialian liverworts (e.g. Lunularia and Plagiochasma), the description is not applicable to M. polymorpha.

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Two naturalized plants of the Euphorbiaceae, Euphorbia prostrata Aiton and an unidentifiable Euphorbia sp. aff. prostrata Aiton, were newly found from the cities of Hiroshima and Hatsukaichi in Hiroshima Prefecture, Japan. In this study, morphology and habitat are described for these two species. In addition, DNA barcoding and phylogenetic analyses based on nr ITS and psbA–trnH sequences were carried out. The sequences obtained from the unidentifiable Euphorbia were different from those of E. prostrata and no identical sequence of plants was found in the database. Additional work is needed to identify the invasive Euphorbia species in Japan.

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