Once while Vishnu and Brahma were quarrelling about which of them was superior to the other, Shiva, in the form of a column of light,appeared beside them. The column seemed to have no beginning or end, stretching upwards and downwards as far as the eye could see. The two gods decided that whoever found the top or the bottom of the column first would be deemed to be superior to the other.So they set out, Vishnu in the form of a boar, and Brahma in the form of a swan. Vishnu descended for aeons together, but could not find the base of the column, and finally gave up the search. Brahma, soaring upwards, was equally unsuccessful in reaching the top. However, he saw a Ketaki flower wafting down, and catching it, returned to the starting point and in a spot of duplicity claimed success ! He waved the flower, which he said he had found at the summit, in Vishnu’s face. But Vishnu doubted his claim and asked Ketaki if it was true. Ketaki said it was true.
The barefaced lie infuriated Shiva and he appeared and cursed the flower never would it be used in worship. Thus Ketaki, till then considered the best among flowers, fell from grace and lost its importance and was never again offered in worship except on Mahashivratri.