Which flower blooms only at night and wilts by dawn?

The flower that blooms only at night and wilts by dawn is the night-blooming cereus. The night-blooming cereus is a member of the cactus family and is native to the deserts of the southwestern United States, Mexico, and South America. The flower is also known as the queen of the night, as it blooms only once a year, at night, for just a few hours.

The night-blooming cereus has large, fragrant, white flowers that can reach up to a foot in diameter. The flowers start to bloom at dusk and are fully open by midnight. By dawn, the flowers start to wilt and close up, and by midday, they are completely gone.

The night-blooming cereus is often grown as an ornamental plant, and many people enjoy staying up late to watch the flower bloom. The plant is also believed to have some medicinal properties, and it has been used to treat a variety of ailments including fever, inflammation, and arthritis.