Sometimes the lotus is compared to the feet, the heart, or the life-giving attributes of the Buddhist female. Moreover it has a history that predates Buddhism as its symbolism was also of Hindu heritage.

For instance, Brahman legend tells the story of how when Brahman, the god of the universe, was creating this universe, he went to sleep on the job; as he slept, the lotus bud appeared from his naval and its petals opened, Vishnu emerged and finished the creation.

Buddha used its four stages to symbolise the four types of people and their distance from enlightenment. … The symbolism of the lotus – Daily News & Analysis

An interesting aside: the molecular structure of a lotus blossom’s surface is such that dirt will not stick to it.  The principal is now being incorporated into artificial coatings.  Among other things, it may virtually eliminate car washing when the technology is perfected.