Differentiating Iris Flowers: Learn About Flag Irises vs. Siberian Irises
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By: Mary H. Dyer, Credentialed Garden Writer
There are many different types of iris, and differentiating iris flowers can be confusing. Some types are known by a variety of different names, and the iris world includes a number of hybrids too, which complicates things even further. Many people wonder how to tell the difference between flag iris and Siberian iris, two common types of iris plants. Read on to learn more about differentiating these flowers.
Flag Irises vs. Siberian Irises
So what is the difference between flag iris and Siberian iris?
Flag iris plants
When people talk about “flag iris,” they are generally referring to wild iris. Flag iris includes blue flag (I. versicolor), commonly found in boggy areas and swamps of the northeastern United States, and yellow flag (I. pseudacorus), which is native to Europe but now found in temperate climates around the world. Both are types of beardless iris.
Blue flag iris is ideal for wildflower gardens where the plant has access to plenty of moisture in spring. It makes a good pond or water garden plant, as it performs well in standing water. This plant, which reaches heights of 18 to 48 inches (.4 to 1.4 m.), displays long, narrow leaves, sometimes gracefully curved. The blooms are typically violet blue, but other colors also exist, including intense violet and white with bright pink veins.
Yellow flag iris is a tall iris with stems that reach heights of 4 to 7 feet (1.2 to 2.1 m.) and upright foliage of about 5 feet (1.5 m.), depending on growing conditions. The ivory or pale to bright yellow blooms may be single or double, and some forms may display variegated foliage. Although yellow flag iris is a lovely bog plant, it should be planted carefully, as the plant tends to be invasive. The seeds, which float, spread readily in running water and the plant may clog waterways and choke out native plants in riparian areas. The plant has done considerable damage to wetlands in the Pacific Northwest and is considered a highly noxious weed.
Siberian iris plants
Siberian iris is a hardy, long-lived type of beardless iris consisting of clumps of narrow, sword-like leaves and slender stems that reach heights up to 4 feet (1.2 m.). The graceful, grass-like leaves remain attractive long after the flowers have faded.
Siberian iris types available in most garden centers are hybrids of I. orientalis and I. siberica, native to Asia and Europe. Although the plants grow well in wildflower gardens and along pond edges, they aren’t bog plants and they don’t grow in water. This is one sure way of differentiating between these and flag iris plants.
Siberian iris blooms may be blue, lavender, yellow or white.
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Growing Iris in our area
In our area, we have seen many old iris blooming in March and April. Many of these that grow like "weeds" are old varieties, and don't need any care.
The modern hybrid varieties are very fancy, and need more care. We who grow many varieties have great fun and a longer blooming season, with early, mid and late blooming iris giving us beautiful blossoms from about mid March through early May. A few varieties rebloom, in late May or during the fall season.
In general, irises are hardy and can be transplanted anytime. The best time for planting is in late summer when they are semi-dormant. This gives them time to establish through the fall and winter, with higher probability for blooming the following spring.
Below is some general information about iris varieties classification and iris planting and growing.
For more local information, please visit some of our events and ask questions.
Are irises bulbs or rhizomes?
Actually, iris come in both bulbs and rhizomes - and there is a difference.
Dutch iris, iris reticulata and iris danfordia (there are others) are bulbs. Bulbs are modified BUDS surrounded by thick fleshy layers, like an onion. They are normally globular in form. They often have either a smooth papery outer layer or one that looks more fiberous. Roots emerge from the bottom (basal plate) when the bulb is actively growing. Offsets are produced off this basal plate. Bulbs tend to "stay put" where you plant them, spreading very slowly over many years.
Bearded iris (Germanica), Louisiana iris, Siberian iris, iris tectorum, iris cristata, spuria iris and aril iris (there are others) are rhizomes. Rhizomes are thickened STEMS that grow horizontally just below the
soil surface. Rhizomes are normally elongated. They are solid, and may be smooth (Germanica, aril) or appear to have segments ringed with fiberous 'hairs' (Louisiana, spuria, Siberian). Roots are produced along the length of the lower surface. Offsets are normally produced at the growing points on the heel of the rhizome, but can occur anywhere along the rhizome. Rhizomes creep along under the surface and can spread rapidly, depending on the type of iris and the cultivar.
Both bulbs and rhizomes (along with croms and tubers) provide the plant with the same service of storing nutrients for growth, only they do it a bit differently.
There are a wide variety of iris classifications. The general categories are bearded and beardless.
The classification list below is brief. For more information, you may go to some national iris web sites, or visit our local ISD events and ask questions.
The "Tall Bearded" (TB) are most common bearded, with an average height of around 36".
Different varieties have different heights and different blooming times in our spring season.
The "Median" types have several classification categories, and heights are less than 28".
Various types have different heights and blooming times, many bloom earlier than TB's:
- "Miniature Dwarf Bearded" (MDB) - these are the smallest of the bearded irises, growing up to 8" in height. They require a significant cold period to prosper, and do not do well in the Dallas area.
- "Standard Dwarf Bearded" (SDB) - these are early bloomers that range from 8" to 16" in height. They are perfect for small areas.
- "Miniature Tall Bearded" (MTB)b- usually blooming with the TBs, these 16" to 27 1//2" irises are dainty, and usually fragrant.
- "Intermediate Bearded" (IB) - blooming between the SDBs and the TBs, these 16" to 27 1/2" perky irises have intermediate sized flowers, and clump well, making them idea for the smaller garden.
- "Border Bearded" (BB) - also in the 16" to 27 1/2" range, these irises bloom with and closely resemble their TB cousins, but are reduced in size to balance their shorter height.
The "Arilbred" types are a hybrid between the common bearded irises described above and the more exotic regelia and oncocyclus aril irises of the middle east and southern Asia. The less aril content, the more similar they are to growing TBs. Most will grow in the Dallas area.
Bearded iris need some cool winter time to be happy for spring growing and blooming.
The "Louisiana" (LA) are most common beardless, with height ranges similar to tall bearded. Varieties bloom over the range of mid April through mid May in our area. These need more moisture (see "Planting" below), and less need for cool winter.
The "Spuria" (SPU) type have some growing similarities to bearded iris, blooming with the late TBs and the LAs. They resemble Dutch iris on steroids, growing to heights of over 40" and producing pampas grass like clumps.
Others: "species", "Siberian", "Japanese", and a few others.
The "Bulbous" iris (e.g. "Dutch Iris") have a bulb-type base rather than rhizomes and bloom very early. Like most bulbs, they die back in the summer and come back in the fall/spring.
There are some bearded iris varieties that rebloom late spring and/or during the fall. Not everything that is labeled a rebloomer will rebloom in Texas. Check with your local growers for varieties that rebloom here.
Some reliable Dallas area rebloomers (all TBs unless otherwise noted):
|Total Recall||Auroralita (SDB)||Senorita Frog (SDB)|
|Violet Miracle||Daughter of Stars||Autumn Circus|
|Destry Rides Again||Autumn Echo||Earl of Essex|
|Say Okay||Cinders (SDB)||Lady Emma (MTB)|
|Autumn Tryst||Queen Dorothy||Happy New Year|
|My Friend Jonathan||Baby Blessed (SDB)||Harvest of Memories|
|Constant Companion (IB)||Lunar Whitewash||Misty Twilight|
|Sugar Snaps (IB)||Jewel Baby (SDB)||Corn Harvest|
|Belvi Queen||Rosalie Figge||I Bless (IB)|
|St. Petersburg||Now and Later||Reincarnation|
|Wizard's Return (SDB)||Cayenne Capers||Darkling (SDB)|
Planting and Growing Bearded Iris
After receiving bearded iris, it is better to plant as soon as possible. If not, store them is a cool dry area until planting time is available. They can survive easily being dry and cool.
When to Plant: Best time is August through late September.
Where to Plant: Bearded iris need at least 4 hours of sun, and more is better. Some afternoon shade is okay in a hot climate. They need well drained soil, such as raised beds, and neutral pH soil.
Soil Preparation: Iris will thrive in garden soils. Heavy clay soil must be improved by adding course sandy material (e.g. play sand, washed sand, etc.) and compost. Some sulfur powder will help neutralize alkaline. Prepare the soil by tilling or turning over the soil with a garden fork to a depth of at least 10 inches. Also some fertilizer may be added in tilling of the soil.
Depth to Plant: Plant iris so the tops of the rhizomes are at the surface, or barely covered, and the roots spread out and down on each side of a slight planting mound.
Distance Apart: Iris are generally planted 12 to 24 inches apart. They may be planted closer for immediate effect, but will need to be thinned out every other year.
Watering: Newly planted iris need some moisture to begin to establish their root system. But it should never be soggy, since it will increase possible iris rot. Let the soil dry before next watering. Periodic deep watering is more beneficial than frequent sprinkling. Rebloomers will like to have a little more watering to prepare for their rebloom.
Fertilizing: For iris in our area, we suggest a light feeding in mid October and mid February. Bearded iris don't like excess nitrogen fertilizer, since it will promote rot. Some suggested fertilizers are 10-20-10, or 13-13-13, or balanced organic fertilizer. Some other fertilizer recipes are also suggested by experts. The fertilizer is applied as a light top dressing, and possibly stirred a little into the top soil. Iris will respond well to a minimum of attention, while they may not thrive with no attention.
Thinning: Generally, iris need to be thinned and divided about every 3 to 4 years. Crowded clumps may slow down blooming.
General Care: We suggest to clean weeds and debris. Iris don't care for mulch on the top soil. Stalks can be cut close to the ground after bloom. Do not cut back healthy leaves, but diseased or brown ones should be removed. Keep diseased foliage out of the compost pile.
- Bacterial soft rot: this is mushy and smelly disease at the base of the plant, or sometimes on the bloom stalk. Cut out and clean out the soft parts, and spray with a 10% bleach solution and maybe a powder, such as Ajax, on the infected area. Also adding some sulfur powder may suppress bacteria.
- Fungal leaf spot: this starts as small brown spots on the new spring leaves. It occurs generally in the spring when there may be some fungus in the ground and the air gets warmer and humid. For this problem, spray with Daconil a few times to stop fungus growing. Later in the season as the humidity goes down, the fungus stops growing. To prevent this problem, spray with Daconil a few times early in the spring, or use a little bit of sprinkling fungicide with the fertilizer in February.
For other growing information, go to AIS Growing Information or visit one of our activities.
Planting and Growing Louisiana Iris
Louisiana Iris need at least 4 hours of sun. These grow well in wet soil, such as a pond, so they don't need well drained soil. That's why they were once called "swamp iris". They prefer slightly acid soil, and they can accept more fertilizer than bearded iris. But they actually tolerate a range of soil types, so they may be planted with some other flowers, such as daisies, daylilies, etc., as long as they can get regular watering, about an inch a week.
For more growing information, go to: SLI Culture of Louisiana Irises
For more information about the Iris Society of Dallas please send us an email.
Bearded, German, Japanese, Louisiana or Siberian: Irises are worldly perennials with more than 300 speciesThe "beard" of a bearded iris is a vivid patch of fuzz on the three downward pointing petals, called falls. The beard helps pollinators land right where they need to to gather iris pollen. (Special to the Democrat-Gazette/JANET B. CARSON)
One of the oldest and best-known perennials in the home landscape is the bearded iris, sometimes called a German iris or a flag. But the genus Iris contains almost 300 species, and many irises have been hybridized extensively.
In the Greek language, the word "iris" means rainbow, which is fitting since the flowers come in a rainbow of colors. Irises have a rich history that dates to A.D. 500. They were brought to the New World by European settlers. Records show them in Virginia gardens as early as the 1600s.
Most species of iris are perennial plants but can be divided into two distinct types — those grown from a bulb, or "bulbous" irises, which include the Dutch iris and the reticulated iris and those that grow from a rhizome, or "rhizomatous" irises. A rhizome is a modified stem that grows horizontally, sending out roots and shoots.
Of the rhizomatous types, there are three classifications — bearded, beardless and crested. Rhizomatous irises include the bearded or German iris, the Louisiana iris, Japanese iris, Siberian iris and the native woodland crested iris.
Iris plants are monocots, meaning their flower parts are in groups of three. In general, three sepals face downward and are referred to as "falls," while the three upturned petals are called "standards."
By far the most common iris grown in gardens is the bearded iris, Iris germanica. After a century of intense hybridization, they are often referred to now as bearded hybrids.
The name refers to the bushy "beards" that appear on the falls of the flower and help pollinators find the pollen.
According to the American Iris Society, there are six different groups of bearded irises based on size: miniature dwarf, dwarf, intermediate, miniature tall, border and tall. Their bloom times range from late winter to early summer. Some newer varieties bloom again in late summer or early fall and are known as "rebloomers."
In Arkansas, the most popular bearded type is the tall bearded iris. Its flowers grow along bloomstalks 28 inches tall or taller.
The rhizomes are planted shallowly, with part of the rhizome exposed above ground — and no mulch should cover the rhizome. A spacing of 12-24 inches is best. They like a well-drained, light soil with at least 6-8 hours of sunlight a day.
If you have heavy soils, amend with organic matter. Fertilize with a complete fertilizer in the spring and again a month after bloom. Avoid putting the fertilizer directly on the rhizome.
A common problem can be the competition of grass and weeds. Make sure you clean the garden well before planting. Once established, bearded irises are very drought tolerant and relatively carefree — but you will need to lift and divide them eventually.
The rhizomes multiply horizontally and can form a mat over time. If they get too crowded they will stop blooming. They should be divided every three to five years, or sooner if their blooms begin to decline.
The best time to divide them is from mid-July to mid-August since the plants are usually dormant then. Since you plant iris rhizomes shallowly, you want to allow time for them to re-establish before cold weather hits.
You can thin a clump, leaving parts of the rhizome mass still in the ground but digging up the whole clump and separating them is more common because the older rhizomes rot away leaving holes where mother plants once stood.
Some varieties are prone to diseases, and so many growers soak their divisions in a 10 percent bleach solution for 10 to 15 minutes, rinsing and then drying them before replanting.
Choose strong rhizomes with healthy fans to replant. Fans are the cluster of leaves that come from the rhizome. When dividing, you want to cut the fan back so it's only 6 to 8 inches tall. Cutting helps sanitation, but it also prevents the wind from uprooting the shallowly planted iris until its roots re-establish.
Bearded irises typically bloom for two to five weeks, depending on the vigor of the plant. When planting, choose early, midseason and late-blooming varieties to extend the flower display in your garden.
A common question is whether it's necessary to cut back the foliage after bloom. Unless you are dividing them, there is no reason to cut the leaves of bearded irises. Many growers do cut the leaves because they have hundreds (or thousands) of iris plants and want to provide better air circulation and sunlight penetration to reduce leaf-spotting diseases.
If you just have a few iris plants in your garden, there is no need to cut the foliage back.
While tall bearded irises are by far the most popular varieties here, there are several other irises that are great garden performers and will thrive in different locations.
Our native crested irises are much smaller plants that love the shade. In the wild they are typically found in deciduous forests in light to fairly heavy shade.
A wild crested iris only grows 6 inches tall, and the rhizomes are near the surface but typically covered with soil or leaf mulch. These little plants have lovely clusters of light blue or violet flowers that last two or three weeks in the spring. There are some white-blooming forms as well.
After bloom, the grass-like foliage can serve as a groundcover. Crested irises do best in a well-drained but rich site. They do not have to be divided unless you want to propagate them, and early fall is the best time to do so.
Beardless rhizomatous irises include the Louisiana, Japanese and Siberian iris plants. They do like full sun but they are planted in the soil, not at the soil level, and they need much more water than their bearded cousins.
Siberian irises like even moisture while Japanese irises like as much water as you can provide -- but neither like to have wet feet in the winter.
Louisiana irises will grow in standing water year-round but will also do well in the ground as long as they don't dry out.
Louisiana irises are native to Louisiana and the Gulf Coast. The wild copper iris is found in Arkansas, too, and like other Louisianas, likes swamps and moist areas. While that is where they grow in the wild, Louisiana irises also tolerate soil moisture conditions in a home garden. But they are not drought tolerant -- they do need some supplemental watering in hot, dry summers.
They need 6-8 hours of sunlight a day but would like a little protection from the hot afternoon sun if possible.
Plant them 1 inch deep in organic soils. They will tolerate heavy clay soils, as they retain moisture well, but the addition of organic matter is helpful. Depending on the variety, mature plant size could be a foot to 6 feet tall, with flowers in a wide range of colors.
The purest red color available in an iris is found among the Louisiana irises.
Cut back the flower stalk after bloom. Clumps spread rapidly in good conditions, so space them several feet apart to give them room to grow.
Japanese irises (Iris ensata) and Siberian irises (Iris siberica) are similar in appearance, but the flowers are typically larger on Japanese irises, and the plants are 3 to 4 feet tall. Japanese iris foliage also has a very distinct raised central rib, which the Siberians do not.
Siberian irises grow 2-4 feet tall and bloom several weeks after bearded irises.
Japanese irises are the last irises to bloom and have the largest and showiest blooms. Japanese irises are planted 3 to 4 inches deep in rich soil.
For both types, keep the soil moist after planting and water if there is not plenty of rainfall, particularly until blooming ends. Both are heavy feeders and should be fertilized with a complete fertilizer in the spring and just before blooming. These plants have large sword-like leaves and can be difficult to transplant once planted. Give them full sun.
These are all great choices for the perennial garden.
The two bulbous irises are planted in the fall along with daffodils and tulips. The Dutch iris is not long-lived in our climate, but showy while it lasts. The reticulated iris is a tougher plant and blooms in early spring. They can colonize and come back each year.
Regardless of which iris you plant in your garden, or if you try them all, they can add much beauty to the landscape.
And if you want to learn more, consider joining an Arkansas iris society.
There are two common sorts of Iris which may be planted directly in the water namely, the European Wild Flag (I. pseudacorus) and the Blue Flag (I. versicolor). The European Wild Flag has large, yellow flowers, the petals of which are drooping. The flowers appear among the luxuriant leaves. The Blue Flag is a familiar flower to most Americans, for what boy or girl has not gotten wet feet gathering it? Both of these sorts will thrive in ordinary garden soil without a great quantity of water.
- 1 Structure
- 1.1 Front
- 1.2 Back
- 1.3 Microanatomy
- 1.4 Development
- 2 Eye color
- 2.1 Genetic and physical factors determining iris color
- 2.1.1 Amber eyes
- 2.2 Different colors in the two eyes
- 2.1 Genetic and physical factors determining iris color
- 3 Clinical significance
- 4 Alternative medicine
- 4.1 Iridology
- 5 Etymology
- 6 Graphics
- 7 See also
- 8 References
- 9 External links
The iris consists of two layers: the front pigmented fibrovascular layer known as a stroma and, beneath the stroma, pigmented epithelial cells.
The stroma is connected to a sphincter muscle (sphincter pupillae), which contracts the pupil in a circular motion, and a set of dilator muscles (dilator pupillae), which pull the iris radially to enlarge the pupil, pulling it in folds.
The circle circumference sphincter constricting muscle is the opposing muscle of the circle-radius dilator muscle. The iris inner smaller circle-circumference changes size when constricting or dilating. The iris outer larger circle-circumference does not change size. The constricting muscle is located on the iris inner smaller circle-circumference.
The back surface is covered by a heavily pigmented epithelial layer that is two cells thick (the iris pigment epithelium), but the front surface has no epithelium. This anterior surface projects as the dilator muscles. The high pigment content blocks light from passing through the iris to the retina, restricting it to the pupil.  The outer edge of the iris, known as the root, is attached to the sclera and the anterior ciliary body. The iris and ciliary body together are known as the anterior uvea. Just in front of the root of the iris is the region referred to as the trabecular meshwork, through which the aqueous humour constantly drains out of the eye, with the result that diseases of the iris often have important effects on intraocular pressure and indirectly on vision. The iris along with the anterior ciliary body provide a secondary pathway for aqueous humour to drain from the eye.
The iris is divided into two major regions:
- The pupillary zone is the inner region whose edge forms the boundary of the pupil.
- The ciliary zone is the rest of the iris that extends to its origin at the ciliary body.
The collarette is the thickest region of the iris, separating the pupillary portion from the ciliary portion. The collarette is a vestige of the coating of the embryonic pupil.  It is typically defined as the region where the sphincter muscle and dilator muscle overlap. Radial ridges extend from the periphery to the pupillary zone, to supply the iris with blood vessels. The root of the iris is the thinnest and most peripheral. 
The muscle cells of the iris are smooth muscle in mammals and amphibians, but are striated muscle in reptiles (including birds). Many fish have neither, and, as a result, their irides are unable to dilate and contract, so that the pupil always remains of a fixed size. 
- The crypts of Fuchs are a series of openings located on either side of the collarette that allow the stroma and deeper iris tissues to be bathed in aqueous humor. Collagen trabeculae that surround the border of the crypts can be seen in blue irises.
- The midway between the collarette and the origin of the iris: These folds result from changes in the surface of the iris as it dilates. 
- Crypts on the base of the iris are additional openings that can be observed close to the outermost part of the ciliary portion of the iris. 
- The radial contraction folds of Schwalbe are a series of very fine radial folds in the pupillary portion of the iris extending from the pupillary margin to the collarette. They are associated with the scalloped appearance of the pupillary ruff.
- The structural folds of Schwalbe are radial folds extending from the border of the ciliary and pupillary zones that are much broader and more widely spaced, continuous with the "valleys" between the ciliary processes.
- Some of the circular contraction folds are a fine series of ridges that run near the pupillary margin and vary in thickness of the iris pigment epithelium others are in ciliary portion of iris. 
From anterior (front) to posterior (back), the layers of the iris are:
- Anterior limiting layer
- Stroma of iris
- Iris sphincter muscle
- Iris dilator muscle (myoepithelium)
- Anterior pigment epithelium
- Posterior pigment epithelium
The stroma and the anterior border layer of the iris are derived from the neural crest, and behind the stroma of the iris, the sphincter pupillae and dilator pupillae muscles, as well as the iris epithelium, develop from optic cup neuroectoderm.
The iris is usually strongly pigmented, with the color typically ranging between brown, hazel, green, gray, and blue. Occasionally, the color of the iris is due to a lack of pigmentation, as in the pinkish-white of oculocutaneous albinism,  or to obscuration of its pigment by blood vessels, as in the red of an abnormally vascularised iris. Despite the wide range of colors, the only pigment that contributes substantially to normal human iris color is the dark pigment melanin. The quantity of melanin pigment in the iris is one factor in determining the phenotypic eye color of a person. Structurally, this huge molecule is only slightly different from its equivalent found in skin and hair. Iris color is due to variable amounts of eumelanin (brown/black melanins) and pheomelanin (red/yellow melanins) produced by melanocytes. More of the former is found in brown-eyed people and of the latter in blue- and green-eyed people.
Genetic and physical factors determining iris color Edit
Iris color is a highly complex phenomenon consisting of the combined effects of texture, pigmentation, fibrous tissue, and blood vessels within the iris stroma, which together make up an individual's epigenetic constitution in this context.  A person's "eye color" is actually the color of one's iris, the cornea being transparent and the white sclera entirely outside the area of interest.
Melanin is yellowish-brown to dark brown in the stromal pigment cells, and black in the iris pigment epithelium, which lies in a thin but very opaque layer across the back of the iris. Most human irises also show a condensation of the brownish stromal melanin in the thin anterior border layer, which by its position has an overt influence on the overall color.  The degree of dispersion of the melanin, which is in subcellular bundles called melanosomes, has some influence on the observed color, but melanosomes in the iris of humans and other vertebrates are not mobile, and the degree of pigment dispersion cannot be reversed. Abnormal clumping of melanosomes does occur in disease and may lead to irreversible changes in iris color (see heterochromia, below). Colors other than brown or black are due to selective reflection and absorption from the other stromal components. Sometimes, lipofuscin, a yellow "wear and tear" pigment, also enters into the visible eye color, especially in aged or diseased green eyes.
The optical mechanisms by which the nonpigmented stromal components influence eye color are complex, and many erroneous statements exist in the literature. Simple selective absorption and reflection by biological molecules (hemoglobin in the blood vessels, collagen in the vessel and stroma) is the most important element. Rayleigh scattering and Tyndall scattering, (which also happen in the sky) and diffraction also occur. Raman scattering, and constructive interference, as in the feathers of birds, do not contribute to the color of the human eye, but interference phenomena are important in the brilliantly colored iris pigment cells (iridophores) in many animals. Interference effects can occur at both molecular and light-microscopic scales, and are often associated (in melanin-bearing cells) with quasicrystalline formations, which enhance the optical effects. Interference is recognised by characteristic dependence of color on the angle of view, as seen in eyespots of some butterfly wings, although the chemical components remain the same. White babies are usually born blue-eyed since no pigment is in the stroma, and their eyes appear blue due to scattering and selective absorption from the posterior epithelium. If melanin is deposited substantially, brown or black color is seen if not, they will remain blue or gray. 
All the contributing factors towards eye color and its variation are not fully understood. Autosomal recessive/dominant traits in iris color are inherent in other species, but coloration can follow a different pattern.
Amber eyes Edit
Amber-colored eyes are extremely rare in humans. They consist of a solid orange/gold color that may contain lighter shades of the same pigment within the iris. This is an unusual occurrence that happens when the yellow pigment pheomelanin is dominant within the iris. Pheomelanin is also found on individuals with green eyes in much smaller amounts. This is because green eyes have a strong presence of both melanin and pheomelanin. Often in poor lighting, one may mistake amber eyes for brown. This also happens when viewed from far away or in pictures with poor lighting, as well. In natural or well-lit areas, though, telling the difference between the two colors is easy. Another common mistake people make is referring to amber eyes as hazel. Although similar, hazel eyes have a stronger presence of melanin with two very distinct colors within the iris (usually green/brown), and often contain many speckles or blotches of mixed hues. 
Different colors in the two eyes Edit
Heterochromia (also known as a heterochromia iridis or heterochromia iridum) is an ocular condition in which one iris is a different color from the other iris (complete heterochromia), or where the part of one iris is a different color from the remainder (partial heterochromia or sectoral heterochromia). Uncommon in humans, it is often an indicator of ocular disease, such as chronic iritis or diffuse iris melanoma, but may also occur as a normal variant. Sectors or patches of strikingly different colors in the same iris are less common. Anastasius the First was dubbed dikoros (having two irises) for his patent heterochromia since his right iris had a darker color than the left one.  
In contrast, heterochromia and variegated iris patterns are common in veterinary practice. Siberian Husky dogs show heterochromia,  [ better source needed ] possibly analogous to the genetically determined Waardenburg syndrome of humans. Some white cat fancies (e.g., white Turkish Angora or white Turkish van cats) may show striking heterochromia, with the most common pattern being one uniformly blue, the other copper, orange, yellow, or green.  Striking variation within the same iris is also common in some animals, and is the norm in some species. Several herding breeds, particularly those with a blue merle coat color (such as Australian Shepherds and Border Collies) may show well-defined blue areas within a brown iris, as well as separate blue and darker eyes. [ citation needed ] Some horses (usually within the white, spotted, palomino, or cremello groups of breeds) may show amber, brown, white and blue all within the same eye, without any sign of eye disease. [ citation needed ]
One eye with a white or bluish-white iris is also known as a "walleye". 
Iridology (also known as iridodiagnosis) is an alternative medicine technique whose proponents believe that patterns, colors, and other characteristics of the iris can be examined to determine information about a patient's systemic health. Practitioners match their observations to "iris charts", which divide the iris into zones corresponding to specific parts of the human body. Iridologists see the eyes as "windows" into the body's state of health. 
Iridology is not supported by quality research studies,  and is considered pseudoscience  by the majority of medical practitioners and eye-care professionals.
The word "iris" is derived from the Greek goddess of the rainbow, because of the many colours of the iris. 
D) Bulbous Iris:
These types of Iris grow from bulbs. They shed their leaves after blooming and become dormant in summer. These types of Iris have short shaped leaves and erect stalks having bright colored flowers. Some Bulbous types of Iris bloom early, while others are late bloomers.
The three main types of Bulbous Iris are: Bulbing Juno, Bulbing European, and Bulbing Reticulate Iris.
1. Bulbing Juno: It is commonly called Junos and is the most common type of Bulbous Iris. It is dormant in summer and grows in mid-winter or early spring. Bulbing Junos are scented flowers. Junos is found in Central Asian countries like Turkey, Iraq, Syria, and also in Afghanistan, where it grows on stony and grassy slopes. Some varieties of Junos also grow in Tajikistan and Uzbekistan. They come in White, Blue, Yellow, and Lavender colors depending on the variety.
Olof, Princess, Dushanbe, and Snow White are a few examples of Bulbing Juno Iris.
2. Bulbing European: These types of Iris are found in Europe. Dutch Iris, Spanish Iris, and English Iris are all Bulbing European Iris. The English and Spanish Iris are very common with florists and in European gardens. Interestingly, both are of Spanish origin. They grow in well-drained soil in a shelter and come in varied colors.
A variety of Bulbing European Iris, known as the Netted Iris, is found in Russia and Northern Iran. It comes in pale blue, deep blue, or purple color and is scented. The flower has a netted surface that gives these flowers the name.
Pixie, Bronze Queen, Golden Harvest, and Purple Sensation are a few names of Bulbing European Iris.
3. Bulbing Reticulate Iris: These scented flowers are the earliest bloomers in spring. They grow only 5-inch tall. Moist and well-drained soil is required for these flowers. They can grow both in the sun and also in part shade. The Reticulated Iris comes in Purplish-Blue, Yellow and White colors. However, the purple color in these flowers is dominant. These flowers bloom for just two weeks.
Harmony, Dan Ford, and Black Iris are the names of Bulbing Reticulate Iris
Interestingly, Dan Ford Iris blooms for even a shorter period than the other Bulbing Reticulate Iris.