Tulips form a genus of spring-blooming perennial herbaceous bulbiferous geophytes. The flowers are usually large, showy and brightly colored, generally red, pink, yellow, or white. They often have a different colored blotch at the base of the tepals, internally. Because of a degree of variability within the populations, and a long history of cultivation, classification has been complex and controversial. The tulip is a member of the lily family, Liliaceae, along with 14 other genera, where it is most closely related to Amana, Erythronium and Gagea in the tribe Lilieae. There are about 75 species, and these are divided among four subgenera. The name "tulip" is thought to be derived from a Persian word for turban, which it may have been thought to resemble. Tulips originally were found in a band stretching from Southern Europe to Central Asia, but since the seventeenth century have become widely naturalised and cultivated. In their natural state they are adapted to steppes and mountainous areas with temperate climates.