Iris japonica - Iris

...In the ninth chapter of the Tales of Ise, the protagonist, who took a short rest here on his way east, is so impressed by the beauty of the iris that he places the five characters of the flower at the top of each line, writing, "As I am accustomed to wearing this kimono, I think of the long journey I have made" (this poem is included in Volume 9 of the Kokinshu as a poem by Ariwara no Narihira). The Noh play Kakitsubata uses this as its subject. The place name Yatsuhashi comes from the fact that "if the water flows like a spider's hand, eight bridges will be built for you" (Tales of Ise).

*Some of the terminology explanations that mention "Iris" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…《伊勢物語》第9段に，東下りの途次ここに少憩した主人公が，カキツバタの美しさにその5文字を各句の上にすえて〈から衣きつつなれにしつましあればはるばる来ぬる旅をしぞ思ふ〉と詠んだとある(《古今集》巻九に在原業平の歌として載る)。謡曲《杜若（かきつばた）》はこれを素材とする。八橋の地名は〈水ゆく河の蜘蛛手（くもで）なれば橋を八つわたせる〉によるという(《伊勢物語》)。…

※「《杜若》」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報