The tolerance to salinity of three Poeciliidae species (Poecilia reticulata, P. sphenops, and Xiphophorus sp.) and the Japanese rice fish (Oryzias latipes ver.) was investigated in small aquarium tanks. The salinity of water in the tanks was raised to various levels, and the survivability of fish in increased salinities was determined. When the salinity was raised to the sea water concentration (35 psu) within a 24-h period, all individuals of three Poeciliidae species died. When the salinity was gradually raised over a period of three days or more, some individuals of two species (P. reticulata and P. sphenops) survived, while all individuals of Xiphophorus sp. died. On the other hand, in four raising periods of the salinity, some individuals of O. latipes ver. survived. Thus, it was shown that the three alien species can survive in sea water. Therefore, there is a possibility of migration of these aliens to other geographical areas through the estuary.

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There have been several reports on cytotypes of Deparia pycnosora sensu lato from Japan. However, previous cytological reports were made before three varieties of D. pycnosora were identified. Thus, the author examined the three varieties to determine their respective cytotypes based on the chromosome number and spore number per sporangium, and ploidy analysis. D. pycnosora var. pycnosora and D. pycnosora var. mucilagina can be diploid (2n = 80), while D. pycnosora var. albosquamata can have a tetraploid sexual cytotype (2n = 160). However, D. pycnosora var. albosquamata can be allotetraploid as its DNA content was slightly smaller than two times that of the diploid varieties.

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There have been many reports on acorn shapes, mostly for forest trees, and few for planted trees in urban areas. Acorn shapes were investigated for five species (Quercus serrata, Q. glauca, Q. myrsinifolia, Lithcarpus edulis, and Castanea crenata) distributed in the city of Musashino, Tokyo. The results revealed that acorns of Q. glauca and Q. myrsinifolia were smaller in length, width, and volume than those of Q. serrata and Lithocarpus edulis. There were differences in length and width of acorns between Q. glauca and Q. myrsinifolia.

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