The occurrence of the Buddhist wonder, a small flower called ‘u-dam- ba-ra’(우담바라), which seats itself on unimaginable places, such as a stony or metallic surface or even the finger of a Buddhist monk, has long caught the public`s attention. The Korean u-dam-ba-ra is not a flower but, in fact, the small eggs of the green lacewing(Chrysopa intima MacLachlan) which hangs in the air from silk stalks. An attempt is made in this article to clarify the historical origin of this belief in the Buddhist wonder embodied in the misunderstood insect eggs. The historical origin of this miraculous Buddhist flower is a species of Indian fig tree, namely udumbara(Ficus racemosa Linn). The mystification of the Indian udumbara flower already happened in the Buddhist traditions of India itself, but the misconception of the green lacewing eggs for the udumbara flower seems to have been formed in East Asia. The complex biological, ecological and religious contexts of the multilayered mystification of an Indian fig tree into the far eastern youtanbaluo(優曇跋羅) are surveyed on the basis of Indian original text materials. The botanical peculiarities of the Indian udumbara reserving the status of the symbol for the vitality and fertility was already recognized in the Vedic traditions of ancient India. Later in the early Indian Buddhist traditions, the image of the udumbara was shifted from that of their impossibility to that of their rareness. This is basically due to the fact that fig flowers are kept inside the syconium, the result of which the flowers are not visible at all from the outside, and the ‘(false-)fruits’ are grown up on the trees. Such an extraordinary impression is reflected in the Chinese name of the fig fruit, i.e. wuhuaguo(無花果, the fruit without flower). Additional botanical and partly relevant zoological features of Indian udumbara, such as the pollination by specified fig wasps, were taken into consideration to give an answer for the question of why the udumbara alone out of the numerous fig tree species in India was elevated to the symbolic status of rareness meaning the immeasurably high value justly comparable to the appearance of the Buddha in this world.