Tulips are flowering bulbs valued in beds and borders for their bright colours in early spring. They are indigenous to mountainous areas with temperate climates, where they are a common element of steppe and winter-rain Mediterranean vegetation. They thrive in climates with long, cool springs and dry summers. Tulips are most commonly found in meadows, steppes and chaparral, but also introduced in fields, orchards, roadsides and abandoned gardens. For horticultural purposes tulips are divided into groups according to their flower characteristics. The groups are: Single early, Double early, Triumph, Darwin, Single late, Lily-flowered, Fringed, Viridiflora, Rembrandt, Parrot, Double late, Kaufmanniana, Fosteriana, Greigii and Miscellaneous groups.