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IRIS
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A large group of popular outdoor ornamentals are commonly known as iris, flag, or Fleur-de-Lis. Because of their multicolored flowers, the genus was named after IRIS, the personification of the rainbow in Greek mythology. This genus comprises about 200 species found in the northern temperate zone, the majority being native to Asia. About 30 species grow wild in North America, predominantly in the eastern United States and the Mississippi delta region. Irises belong to the family Iridaceae, which includes crocuses, freesia, and gladiolus.
The irises are perennial herbs that are divided into two divisions, those arising from bulbs and those from horizontal underground rhizomes. They have linear, grasslike or swordlike leaves, and large, showy flowers that are regular and, despite their elaborate appearance, relatively simple. The ovary is connected to a short tube that is attached to three sepals, known as falls because they usually droop. The upper surface of each fall is usually bearded or crested. Three petals, called standards, alternate with the sepals and are upright. Three styles, which are petallike extensions of the ovary, arch over the base and midsection of each fall. Between each style and fall is a single stamen, which is the male organ of the flower. The arrangement of the style and fall ensures cross-pollination of the flowers by insects. As an insect moves through the passageway between the style and fall, it deposits pollen from the previous flower on the stigma near the tip of the style. It then reaches the stamen, brushing against the flower's pollen and carrying it off to other flowers.
Many horticulturally important species, hybrids, and cultivars are grown. The common garden irises of the United States are usually divided into bearded, beardless, and crested irises, all of which are rhizomatous, and bulbous varieties. Bearded irises, which are by far the most popular group, are native to the Old World and have been widely cultivated since ancient times. The Fleur-de-Lis, or German iris, Iris germanica, is the species of bearded iris that is most commonly grown. It is a source of orris root, used in perfumes and tooth powders. Although not as popular, many of the beardless irises, native to Asia, are also cultivated. This group includes the Japanese iris, I. kaempferi, the Siberian iris, I. sibirica, and the oriental iris, I. orientalis. Bulbous irises, mostly native to the Mediterranean region, are the florists' irises that are grown in greenhouses for cut flowers in winter. Two common species are the Tangiers iris, I. tingitana, and the Spanish iris, I. xiphium. Very few crested irises are cultivated in the United States. The slender iris, I. gracilipes, is a crested iris that is occasionally grown in rock gardens.
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