The Japanese word udonge (優曇華) was used by Dōgen to refer to the flower of the uḍumbara tree in chapter 68 of the Shōbōgenzō (Treasury of the Eye of the True Dharma). Dōgen places the context of the udonge flower in the Flower Sermon given by Gautama Buddha on Vulture Peak. The udonge flower may be symbolic of mind to mind transmission between the teacher and the student, in this case, Gautama Buddha and Mahākāśyapa.