ツツヤナギモは1935年に記載されたツツイトモとヤナギモの推定雑種である．本雑種は原記載以降の記録が乏しく，消滅の可能性が危惧されていた．ツツヤナギモを含めた狭葉性ヒルムシロ属植物の雑種は親種間の識別形質が少ないため同定が難しい．そこで，愛媛県から80年ぶりに再発見したツツヤナギモの形態的特徴と遺伝的特性を明らかにすることを目的に研究を行った．分子遺伝解析から，全4産地の推定ツツヤナギモはヤナギモを母系親，ツツイトモを父系親とする一方向性の雑種であった．形態的解析から，ツツヤナギモの癒合した托葉はツツイトモより切れ込みが深いがヤナギモのように分離していなかった．ツツヤナギモの花はヤナギモに比べ小型で雌蕊は花被に覆われ，柱頭は歪に変形していた．ツツヤナギモの葉形態と花序はツツイトモと類似し，花序軸の花間が伸長しない点はヤナギモに類似していた．

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日本に分布するオオバウマノスズクサとアリマウマノスズクサ（別名： ホソバウマノスズクサ）の識別においては，葉形態に基づく混同がしばしば見受けられる．葉が心形であるものがオオバウマノスズクサ，三裂のものがアリマウマノスズクサと区別されることがある．しかし，これら2種それぞれに心形葉～三裂葉がみられ，種内のみならず個体内においても葉形態は変異に富み，またその変異は種間においても連続的である．一方，これら2種は花形態により明確に区別され，オオバウマノスズクサは舷部が黄緑色で広倒卵形，アリマウマノスズクサは舷部が濃紫褐色で倒三角形である．本調査では，オオバウマノスズクサとアリマウマノスズクサの分類学史を踏まえ，混同している状況を整理することで，これら2種の正しい識別形質を普及することを目的とする．

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The pentaploid Pteris × pseudosefuricola (2n = 145), a hybrid between P. cretica (apogamous 3x) and P. multifida (sexual 4x), was newly recorded from Shizuoka and Tochigi Prefectures, Japan. The pinnae are somewhat malformed with irregularly incised margins. The tips of veins in sterile pinnae often reach cartilaginous margins as in P. cretica, but sometimes end short of margins as in P. multifida.

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Orchidaceae, a family of the widespread flowering plants, is reported about 60 species from Shimane prefecture. More than 50% species of Shimane Orchidaceae plants were estimated distributed in Oki islands, an isolated archipelago about 80 km far from Shimane peninsula, and most of them are endangered species. We confirmed the geographical distribution of Orchid Plants in Oki Islands and discuss their conservation status.

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We conducted a preliminary survey of the flora at Mt. Mahiru. Mt. Mahiru (1,059 m alt.) is located in the southern part of the Mahiru Mountains, Tohoku district, Japan, and supposedly harbors a wide diversity of northern plants in Japan, although there has been few studies carried out for the flora. On July 30, 2015, we took a route from Akakura-tozan-guchi to the summit of Mt. Mahiru, and collected plants along the trail and on an alpine meadow around the summit. We collected 98 species of vascular plants, including several species that are rarely seen below 1,300 m alt. in Tohoku district, or below 1,700 m alt. in the central or western part of Honshu. Mt. Mahiru is one of the non-volcanic mountains of heavy snowfall with precipitous valleys in the northern Japan, which suggests that it has kept a suitable condition for montane flora without interruptions by volcanic activities. Further studies on the flora and vegetation of the mountain would provide valuable information on a history of the flora of Japan and on a conservation framework of the biodiversity in Japan.

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Angelica dahurica (Umbelliferae) is distributed in Honshu, Shikoku and Kyushu Islands in Japan, and no recent records from Kanto District in Honshu Isl. Some populations, ca. 300 flowering plants in total, were found growing in the field at Sakura River in Kanto District. Here, we report the discovery of the populations and the results of specimen survey in the herbaria.

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Najas guadalupensis (Sprengel) Magnus subsp. floridana (R. R. Haynes et W. A. Wentz) R. R. Haynes et C. B. Hellquist (Hydrocharitaceae) was recorded from a brackish pond in Ehime Prefecture, Shikoku, as the second locality of the species in Japan. A specimens of the species was proved to have been collected in 1923 from the same area. The origin of the species in Japan was discussed.

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A population of Polygala tatarinowii Regel, an endangered annual herb in Japan, was found near Abukuma Limestone Cave, Tamura City, Fukushima Prefecture, Japan. It could be one of the largest population of the species in Japan, where more than a thousand plants grew on dry meadows beneath limestone bluff or on the flower garden surrounding the Limestone Cave.

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