Which flower

Once long ago there lived two Rulers of different lands famed for their wisdom as well as their beauty.
The Queen of Sheba and King Solomon.
Upon his visit to her land the queen decide to test King Solomon’s wisdom by a series of tests in riddles.
He passed each one with ease until she led him into a room filled with flowers of every shape and colour.
The Queen had the finest craftsmen and magicians in her land construct the flowers so that they look exactly like the real flowers from her garden. “The test” she told King Solomon “is to find the one real flower amongst the thousands of artificial ones”.
King solomon looked carefully from flower to flower and back again, searching for even the smallest of difference.
He looked for any sign of welted leaves or petals but found lifelike leaves and petals in all conditions on every flower. And fragrance was of no help as well for the room was filled with fragrances.
“Please” King Solomon pleaded “the room is so warm. Could we open the curtains and let in a breeze? The fresh air will help clear my head for thinking”
The Queen of Sheba kindly agreed and within minutes after the curtains opened King Solomon new which of the many flowers was the real one.
How did he know?