Ryunosuke Akutagwa loved plants. He loved to have flowers in his room, such as carnations or hyacinths in a vase or Christmas roses in a pot. He not only made haiku and waka about various flowers but also referred to a variety of plants in his letters, travel writings, and other works. His unrequited love was always expressed by flowers in waka. In the Kuzumaki Archive there are numerous fragments of writings classified as "Plants notes" or "Plant myths notes" which show his interest in plants and flowers during his childhood and youth. Akutagawa copied passages of flower fortune-telling, translations of English poems about flowers, some of which may contain his own translations, and tales and myths about metamorphoses into flowers. His drawings of trees seem to represent himself. Symbolic trees are found in his writings about his own life: a gingko tree in his kindergarten, a poplar in his junior high school, and a lime tree in his senior high school. His special interest in metamorphoses into sacred flowers is found in Marsh, St. Christopher, Jyuriano Kichisuke, and Ojyo Emaki. The writer's keen interest in Baudelaire's "forget-me-not" used in Marsh, which actually does not exist in Baudelaire's prose poem 54 "L'invitation au voyage", was aroused by a mistranslation of "revenez-y" as "forget-me-not" and must have been connected to Hakushu Kitahara and Rofu Miki's collection of poems entitled Forget-me-not. The forget-me-not is one of Akutagawa's symbolic "blue flowers". His love and knowledge in plants significantly informs his creative imagination.