Iris

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iris,

common name for members of the genus Iris of the Iridaceae, a family of perennial herbs that includes the crocuses, freesias, and gladioli. The family is characterized by thickened stem organs (bulbs, corms, and rhizomes) and by linear or sword-shaped leaves—small and grasslike in the crocuses and blue-eyed grasses. It is widely distributed over the world except in the coldest regions and is most abundant in S Africa and in tropical America. Almost all of the family's 90-odd genera include commercially valuable ornamentals. The iris family is closely related to the lily and amaryllis families, differing from them in having three stamens rather than six. The cultivated irises (genus Iris), freesias (genus Freesia), and gladioli (genus Gladiolus) show a wide variety of colors in their large, usually perfumed blossoms; they are mostly hybrids of Old World species. The many species of wild iris are most common in temperate and subarctic regions of North America, where they are often called flags, or blue flags. The fleur-de-lis is thought to have been derived from the iris, and the flower of the Greek youth HyacinthHyacinth
or Hyacinthus
, in Greek mythology, beautiful youth loved by Apollo. He was killed accidentally by a discus thrown by the god. According to another legend, the wind god Zephyr, out of jealousy, blew the discus to kill Hyacinth.
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 may have been an iris. Orrisroot, a violet-scented flavoring used in dentifrices, perfumes, and other products, is prepared from the powdered rhizomes of several European species of iris. The freesias, native to S Africa, characteristically bear their blossoms on a horizontal extension of the stem. The crocuses (genus Crocus), which usually bear a single yellow, purple, or white blossom, are native to the Mediterranean area and to SW Asia. One species, saffronsaffron,
name for a fall-flowering plant (Crocus sativus) of the family Iridaceae (iris family) and also for a dye obtained therefrom. The plant is native to Asia Minor, where for centuries it has been cultivated for its aromatic orange-yellow stigmas (see pistil).
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, is cultivated commercially for a yellow dye made from the pollen; the unrelated meadow saffron or autumn crocus and the wild crocus or pasqueflower belong to the lilylily,
common name for the Liliaceae, a plant family numbering several thousand species of as many as 300 genera, widely distributed over the earth and particularly abundant in warm temperate and tropical regions.
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 and buttercupbuttercup
or crowfoot,
common name for the Ranunculaceae, a family of chiefly annual or perennial herbs of cool regions of the Northern Hemisphere. Thought to be one of the most primitive families of dicotyledenous plants, the Ranunculaceae typically have a simple
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 families respectively. Other members of the family found in the United States are the blue-eyed grasses (genus Sisyrinchium) with small clusters of blue, white, or purplish flowers, ranging from Canada to Patagonia, and the celestial lily (genus Nemastylis) with pairs of blue flowers, ranging from the Kansas prairies to Tennessee and Texas. Irises are classified in the division MagnoliophytaMagnoliophyta
, division of the plant kingdom consisting of those organisms commonly called the flowering plants, or angiosperms. The angiosperms have leaves, stems, and roots, and vascular, or conducting, tissue (xylem and phloem).
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, class Liliopsida, order Liliales, family Iridaceae.

Iris,

river: see Yeşil IrmakYeşil Irmak
, anc. Iris, river, c.260 mi (418 km) long, rising NE of Sivas, N Turkey. It flows NW, then NE, past Tokat and Amasya into the Black Sea near Samsun.
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.

iris:

see eyeeye,
organ of vision and light perception. In humans the eye is of the camera type, with an iris diaphragm and variable focusing, or accommodation. Other types of eye are the simple eye, found in many invertebrates, and the compound eye, found in insects and many other
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.

Iris

(ī`rĭs), in Greek mythology, goddess of the rainbow; daughter of Electra and Thaumas. She was often represented as a messenger of Zeus and Hera.

Iris

 

(in electron and ion optics), an opening in a conducting plate; used to limit the cross section and vary the expansion (aperture) angle of a charged-particle beam. A round iris under a potential V and placed in an external electrical field is the simplest electrostatic lens. If E1^ and E2 are equal to the field intensity along different sides of the plate at a distance from the aperture, the focal length of such a lens is approximately f = 4ø/ (E1 - E2) where ø is the potential at the center of the iris. Depending on the sign of f, an iris may be a converging or diverging lens. Combinations of irises under different potentials are also electrostatic lenses.

REFERENCE

Glaser, V. Osnovy elektronnoi optiki. Moscow, 1957. Sections 77 and 89. (Translated from German.)

Iris

 

a genus of plants of the family Iridaceae. They are perennial rhizomatous herbs with sword-shaped or linear leaves. The flowers are large, with a brightly colored corolliform perianth; the ovary is three-celled and inferior; and the fruit is a trihedral, many-seeded pod.

There are about 200 species, distributed throughout the northern hemisphere; in the USSR there are about 60 species. The iris species that form tubers and bulbs are often subdivided into the genera Junona, Xiphium, Iridodictum, and Gynandriris. Irises are widely used for ornament, especially varieties of the species I. kaempferi, I. hybrida, I. spuria, and I. iberica. They grow best in sunny places with well-drained soil. The orrisroot is obtained from the rootstocks of some irises, and a coarse fiber for making brushes is produced from the leaves of the species I. songarica.

REFERENCES

Rodionenko, G. I. Rod Iris. Moscow-Leningrad, 1961.
Rodionenko, G. I. Irisy. Moscow, 1961.

G. I. RODIONENKO


Iris

 

a part of the anterior portion of the eye in animals and man that is located between the vitreous and anterior chambers. The iris is a thin and movable diaphragm with a pupillary aperture in the center; light is regulated through the pupil and onto the retina by the contraction and dilation of the aperture.

The iris is composed of both retinal and uveal structures. The retinal, or posterior, surface consists of two pigmented epithelia. The posterior epithelium is covered by an internal restricting membrane and is a continuation of the retina and the ciliated epithelium. The anterior epithelium is a continuation of the pigmented epithelium of the retina and the ciliary body. The neuroepithelial muscles of the iris are the sphincter, which constricts the pupil, and the dilator, which widens the pupil. They are formed from the anterior epithelium. The sphincter is innervated by parasympathetic fibers of the oculomotor nerve and the dilator is innervated by sympathetic nerves.

The uveal, or mesodermal, surface of the iris is also called the anterior surface. It is a continuation of the vascular layer of the ciliary body and the vascular coat and is composed of exterior reticular and deep vascular layers. The uveal surface is covered with endothelium that extends from the cornea. At the level of the restricting membranes of the iris is the barrier that separates blood from the eye. The anterior surface of the iris is divided into a peripheral, or ciliary, zone, which contains both the reticular and vascular layers, and a pupillary zone, which is the lesser circle of the iris and contains the sphincter. The exterior layer of stroma atrophies in the pupillary zone.

The blood vessels of the iris originate in the vascular circulus major located along the margin of the peripheral zone and are positioned radially. In man, they anastamose into the arterial and venous arches of the vascular circulus minor, 1.5 mm from the pupil margin. No independent lymphatic system has been discovered in the iris. The stroma of the iris is composed of thin collagenic and elastic trabeculae. The predominate cells of the stroma are chromatophores, which determine eye color; man has only melanocytes, while birds, reptiles, and amphibians have iridophores and lipophores in addition to melanocytes. There are also fibroblasts and granular plasma cells in the stroma. The color and architectonic of the uveal part of the iris are determined by species and racial characters and change with age.

Inflammation of the iris (iritis) accompanies traumas and various infectious and metabolic diseases; as a rule, there is also inflammation of the ciliary body.

O. G. STROEVA

iris

[′ī·rəs]
(anatomy)
A pigmented diaphragm perforated centrally by an adjustable pupil which regulates the amount of light reaching the retina in vertebrate eyes.
(botany)
Any plant of the genus Iris, the type genus of the family Iridaceae, characterized by linear or sword-shaped leaves, erect stalks, and bright-colored flowers with the three inner perianth segments erect and the outer perianth segments drooping.
(electromagnetism)
A conducting plate mounted across a waveguide to introduce impedance; when only a single mode can be supported, an iris acts substantially as a shunt admittance and may be used for matching the waveguide impedance to that of a load. Also known as diaphragm; waveguide window.
(optics)
A circular mechanical device, whose diameter can be varied continuously, which controls the amount of light reaching the film of a camera. Also known as iris diaphragm.

iris

of Tennessee. [Flower Symbolism: Golenpaul, 642]

Iris

messenger of the gods. [Gk. Myth.: Kravitz, 130; Gk. Lit.: Iliad]

iris

emblem of the trinity in da Vinci’s “Madonna of the Rocks.” [Plant Symbolism: Embolden, 26]
See: Trinity

iris

1. the coloured muscular diaphragm that surrounds and controls the size of the pupil
2. any plant of the iridaceous genus Iris, having brightly coloured flowers composed of three petals and three drooping sepals
3. a form of quartz that reflects light polychromatically from internal fractures

IRIS

(body)
Institute for Research in Information and Scholarship of Brown University (Providence RI).

Iris

(2)

IRIS

(1) The name of SGI's first graphics terminals and workstations. The name was later used for SGI's high-availability software for its servers (IRIS FailSafe).

(2) (Infrastructure for Resilient Internet Systems) See DHT.

Iris

(dreams)
An iris is a spring flower that symbolizes several very positive and uplifting conditions. In Japan, it is believed that the iris has the power to purify the body and protect the household from disease and evil. Iris is also a God in Greek mythology. She is a messenger who represents the link between heaven and earth and between gods and men. This is a very interesting and specific dream symbol. In order to figure out what it means to you personally, consider your current needs. Do you have a need for purification and safety or are you looking for inspiration?