Living in the shadows: Gastrodia orchids lack functional leaves and open flowers

Non‐photosynthetic plants dependent on fungi have long fascinated botanists and mycologists. The genus Gastrodia (Orchidaceae) contains more than 100 achlorophyllous species, including some species recently discovered in Japan and Taiwan which produce only closed self‐pollinating flowers. To date, Gastrodia is probably the only genus containing species with only closed flowers, which has been verified by a decade of monitoring hundreds of individuals. Here, the unique characteristics of the genus Gastrodia have been reviewed, emphasizing the reproductive biology of these newly described species that neither photosynthesize nor bloom. Investigation of such species that scarcely resemble other plants may paradoxically enhance our understanding of plants more broadly. 光合成をやめ菌類に寄生する植物 (菌従属栄養植物)は、長年にわたり植物学者や菌類学者を魅了してきた。中でもオニノヤガラ属は、100 種以上の種からなり最も種数の多い菌従属栄養性の属として知られる。興味深いことに、本属からは、近年日本や台湾で、開花から結実までの間ずっと花が閉じたままの新種が複数報告された。ここでは、閉鎖花しかつけないこれらの新種を中心にオニノヤガラ属のユニークな生態を紹介する。開花も光合成せず「植物」という言葉から想起される概念と矛盾する性質を持つオニノヤガラ属植物について深く理解することで、逆説的ではあるが植物全体に対する理解を深めることができるだろう。 Non‐photosynthetic plants dependent on fungi have long fascinated botanists and mycologists. The genus Gastrodia (Orchidaceae) contains more than 100 achlorophyllous species, including some species recently discovered in Japan and Taiwan which produce only closed self‐pollinating flowers. To date, Gastrodia is probably the only genus containing species with only closed flowers, which has been verified by a decade of monitoring hundreds of individuals. Here, the unique characteristics of the genus Gastrodia have been reviewed, emphasizing the reproductive biology of these newly described species that neither photosynthesize nor bloom. Investigation of such species that scarcely resemble other plants may paradoxically enhance our understanding of plants more broadly.