Tulipa is a genus in the Liliaceae family from Europe, western Asia to central Asia and North Africa. A book written in 2006 by Richard Wilford is a good source of information. There are about 100 species and thousands of cultivars and confusion about names as many species have been called by different species names over the years. In 2013 an article Tiptoe through the tulips describes history and uses molecular phylogenetics to assist in classification . Although very popular, it is not always easy to grow. Gardeners in warm climates find they do not have the cold temperatures required to initiate bloom and except for the first year after purchasing may only see leaves. To continue to have blooming plants, bulbs must be lifted and refrigerated for 4 to 6 weeks before planting in late fall.
Tulips are also prone to disease. Tulip fire (Botrytis tulipae) can cause eventual loss of the bulbs as it is retained in the soil and withered skins of the bulbs. Tulips are also prone to virus. There are photos and information about the different viruses that plague this genus on our wiki Virus page. A few of the same photos below by Janos Agoston show examples of this:
Information and pictures of a specific species can be found by looking on the wiki Tulipa species pages or by clicking on the specific link in the table below. The hybrid page describes the divisions/groups and shows examples. Photos of named cultivars can be found on that page.