"Krokus" was Greek for the pale purple saffron crocus, cultivated since prehistoric times. Its threadlike red stigmas are used to color and flavor food. At $400 a pound, saffron is the world's costliest spice. It takes 5,000 blossoms - an acre's worth - to make an ounce! In the Middle Ages, this "vegetable gold" was used to make a color to substitute for gold leaf.
Today, lilac means "purple." It's also a bloom that can be purple, white, red, pink, or blue. But the word lilac originally meant blue. Lilac began as a Persian word, nylak("bluish") for the flower, then became laylak in Arabic. Its botanical name, Syringa, is from the Greek syrinx, "pipe," because its pithy stems could be hollowed out and made into pipes. Among arborists, lilacs - so prevalent on American farms - are known as anchors of civilization.
SOURCES: '100 Flowers and How They Got Their Names,' by Diana Wells.