Iris is the largest genus of the family Iridaceae with up to 300 species – many of them natural hybrids.Nearly all species are found in temperate Northern hemisphere zones, from Europe to Asia and across North America. Although diverse in ecology, Iris is predominantly found in dry, semi-desert, or colder rocky mountainous areas. Iris is extensively grown as ornamental plant in home and botanical gardens. Presby Memorial Iris Gardens in New Jersey, for example, is a living iris museum with over 10,000 plants, while in Europe the most famous iris garden is arguably the Giardino dell'Iris in Florence (Italy) which every year hosts a well attended iris breeders' competition. Irises, especially the multitude of bearded types, feature regularly in shows such as the Chelsea Flower Show. For garden cultivation, iris classification differs from taxonomic classification. Garden iris are classed as either bulb iris or rhizome iris with a number of further subdivisions. Bearded iris are classified as dwarf, tall, or aril. In Europe, the most commonly found garden iris is a hybrid iris (falsely called German iris, I. germanica which is sterile) and its numerous cultivars.