分類BUNRUI 第４巻２号　原著論文要旨

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東北地方にみられるエンレイソウ属植物の集団動態　I. 秋田県田沢湖付近刺巻湿原の調査
福田一郎・堀井雄治郎

Abstract
About 1,000 plants of Trillium camschatcence (2n=2x=10) are growing well in the Sashimaki marshland (5 hectare area ) near Lake Tazawa in Tohoku district. These plants are located in the most southern limit of their distributions (Trillium camschatcense). 13 plants of Trillium apetalon (2n=4x=20) also grow there. Only 3 plants of Trillium yezoense (2n=3x=15) have been found growing in this area. By means of chromosome analysis of cold-induced banding karyotype, it has been confirmed that their plants are hybrid between T. camschatcense and T. apetalon.

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ニッコウオオズミの再発見とその分類の再検討
池谷祐幸

Abstract　
"Nikko-ohzumi”, which was discovered at the side of Lake Chuzenji in Nikko (Tochigi Pref.) and described as a new variety, Malus baccata var. nikkoensis, by Asami(1927) but ignored for a long time, was rediscovered. A detailed morphological reexamination indicated that it is impossible to separate this variety from var. mandshurica by tooth height and shape of the sepals, which were considered to be the distinguishing characters by Asami. The geographical distribution of M. baccata var. mandshurica (including var. nikkoensis) in Honshu was also reexamined. Malus baccata var. mandshurica grows disjunctively in the northern Tohoku district, the Chubu district (Nagano Pref. and Yamanashi Pref.) and Nikko. At Nikko, only about 60 plants were discovered and it is questionable whether this population is regenerating.

要旨　浅見與七博士がMalus baccataの新変種var.nikkoensisとして記載したニッコウオオズミと思われる植物を，日光中禅寺湖畔において再発見した．この植物に関して，原記載においてエゾノコリンゴ(M. baccata var. mandshurica)との識別形質とされた萼裂片の形態および葉の鋸歯の形状を中心に再検討した結果，独立な変種としては扱えず，エゾノコリンゴに含めるべきであると結論した．また，本州におけるエゾノコリンゴの分布についても検討し，日光の個体群は北東北，中部いずれの分布域からも離れた隔離個体群であることが判明した．この集団の現存株数は60株ほどであり，実生・稚樹等の更新も殆ど行われておらず，今後の存続が懸念される．

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