ミズニラ属の自然誌と分類  [in Japanese] Natural history and taxonomy of Isoetes (Isoetaceae).  [in Japanese]

ミズニラ属の形態,胞子,繁殖様式,細胞学及び代謝について総説した。塊茎,根,葉,胞子嚢の形態学的解剖学的特徴について述べ,それらの分類学的意義について論じた。大胞子と小胞子の形態や変異をまとめた。有性生殖,無融合生殖,栄養生殖を説明し,胞子発芽を解説した。これまで発表のあった世界中の染色体データーをまとめた結果,本属には2倍体(2n=22)から12倍体(2n=132)の倍数性シリーズがあること,8種に種内倍数性があること,調べられた81分類群では2倍体が27,4倍体が30と2,4倍体の割合が高いこと,13の自然雑種があること,等が明らかとなった。これらの結果は,本属において雑種形成と染色体倍加による網状進化が一般的であることを示している。最後に日本産ミズニラ属の分類と類縁について説明した。

On the basis of a review of earlier studies including those of the author, our current knowledge on morphology, palynology, reproduction mode, cytology and metabolism of the genus Isoetes (Isoetaceae; Pteridophyta) were summarized. Morphological and anatomical features of corms, roots, leaves, sporangia, mega- and microspores and spore germination, as well as their taxonomical values, were discussed. All chromosomal data available throughout the world show the presence of a polyploid series from 2x (2n=22) to 12x (2n=132) and eight species to have intraspecific polyploidies. Out of 81 taxa whose chromosome numbers were reported, 27 are diploids, 30 tetraploids, and 13 natural hybrids. Isoetes thus shows a reticulate evolution through hybridization and polyploidization. A variety of reproduction mode, i.e., sexual, apomictic and vegetative reproduction was explained. A diagnostic key to Japanese taxa comprising four species, one hybrid (Isoetes × michinokuana), and two varieties was also provided, and in addition phylogenetic relationships among them was discussed.