The word "Iyo" is the name of our region often used customarily instead of "Ehime Prefecture" , and "Yugeta" is the wooden boards threw over a hot spa used as steps to get in the spa. Seems they didn't have any buildings or roofs at the time (Dogo Hot Spring Main Building was reconstructed in 1894), and hot spring were everywhere. Because the spa was famous area for bathing those times, and the word "Iyo-no-yugeta" was a kind of fashionable illustration for "many" used among the nobility in Kyoto, the capital of Japan then. So probably they would have had described that "Beautiful flowers like Iyo-no-yugeta", instead of saying "Many beautiful flowers."
Picture (c) copyrights, Matsuyama City Office