About 300 species of flowering plants belong to the genus Iris. These species include some of the most popular and varied garden flowers in the world. The genus is most diverse in the north temperate zone, but some of its most beautiful species are native to the Mediterranean and central Asia. The iris is (arguably) the fleur-de-lis of the French royalist standard. It is a common flower in Japanese flower arrangements and a very important cut flower in the floral business. It is also the source of orrisroot, from which “essence of violet” perfume is made. Taxonomy.
Irises are either bulbous or rhizomatous (with thick creeping underground stems). In species with a rhizome, the stem is usually horizontal, robust, and ringed with leaf scars. It often grows partially exposed but is firmly rooted in the soil. Species of Iris native to southwestern Europe generally produce bulbs. This kind of stem is short and cone-shaped, and many leaf bases grow from it, one inside the other. These bases are seamless and constitute the bulk of the bulb. Bulblets arise from the stem, between the leaf bases, to propagate the plant.
The flowers usually have three sepals, three petals, and three broad stigma branches that can receive pollen. The pollen-producing anthers are hidden under the stigma branches. Irises have six flower parts that look like petals. The six petals on the inside are called standards, and the six petals on the outside are called falls. These parts of the flower are above the ovary (inferior ovary), which is made up of three carpels joined together to make one pistil. Ovules within the ovary portion become seeds, and the ovary matures into dry capsule fruits.
Best known are the bearded, or German, group—the common garden irises. These are largely hybrids of pale blue Iris pallida, yellow I. variegata, purple-blue I. germanica, and perhaps other southern European species. They are hardy rhizomatous types with strong sword-shaped leaves and flower stems up to 3 feet tall that have three to many flowers. With the introduction in 1900 of taller, heavier, larger-flowered I. mesopotamica, even bigger hybrids were made. Many of them smelled good and came in a wide range of colors and combinations, with “beards” on the falls that were often very different from the rest of the plant. A lot of dwarf bearded irises flower in early spring. They are mostly different types of the almost stemless I. pumila and the taller I. lutescens, both from dry rocky places in southern Europe.
Best known of the beardless rhizomatous group is perhaps the water-loving Japanese iris (I. ensata), frequently featured in Japanese watercolors. Its almost flat flowers consist of long, somewhat drooping falls that surround narrower, shorter standards. The Siberian iris (I. sibirica comes from grasslands in central and eastern Europe. It has thin, straight stems with bunches of violet-blue or white flowers on them. Similar but shorter and more sturdy, I. spuria has round falls, short standards, and rather lax foliage. The yellow, or water, flag (I. pseudacorus) is a swamp plant native to Eurasia and North Africa; the blue flag (I. versicolor) occupies similar habitats in North America.
Two outstanding bulbous irises are both from mountains of Spain. They have narrow standards, somewhat broader falls, and spiky linear foliage. Spanish iris (I. xiphium), violet with yellow or yellow-spotted falls, grows in damp sandy places. English iris (I. xiphioides), so named because of its popularity in British horticulture, bears bright blue flowers. Dutch irises are sturdier, earlier-flowering hybrids created in the Netherlands. Special 30% offer for students! Finish the semester strong with Britannica.
Of all the captivating flowers that decorate our gardens few possess the regal elegance of the iris. From its sword-shaped leaves to the intricate architecture of its sensuous blooms the iris showcases a unique beauty. But behind that beauty lies some complexity, especially when it comes to identifying the various parts that make up this fascinating flower.
In this article we’ll take a close look at what makes an iris bloom so distinctive and explain the function of each component. Understanding the anatomy of an iris will help you appreciate how this plant has adapted evolved and been bred into the stylish varieties we love today.
The Main Sections of the Iris Plant
There are two basic sections that make up an iris plant:
Rhizomes
These modified underground stems store food for the iris plant. Each season, new roots and shoots (leaf fans and flower stalks) emerge from the rhizome. As the rhizomes grow horizontally, they allow the iris to propagate and form large clumps.
Leaves
The iris has long, upright leaves with a sword-like shape. Leaves emerge in fan-shaped clusters from the rhizome. The slender flower stalks grow up between the leaves, supporting the iris blooms.
The Parts of the Iris Flower
Now let’s examine the intricate iris bloom Here are the key components
Perianth
The perianth refers to all the floral leaves of the iris bloom, including both petals and sepals (see below).
Sepals
Though they resemble petals, the large, showy, ruffled “falls” that droop down and out from the bloom are actually specialized sepals. There are 3 sepals per iris flower. They attract pollinators with their vivid colors and nectar guides.
Petals
The smaller, upright petals are called “standards.” They flank the sepals, growing in an opposite arrangement. The standards may be quite small or prominent, depending on the iris variety.
Pistil
The female reproductive organ has 3 main parts:
- Stigma – The lip-like structure that receives pollen
- Style – The arm-like branch extending from the stigma
- Ovary – Located at the base of the flower, it houses the ovules and develops into the seed pod after fertilization
Stamen
The male pollen-producing organ consists of:
- Filament – The slender stalk supporting the pollen-filled anther
- Anther – The pollen sac that splits open to release grains of pollen
Beard
This fuzzy caterpillar-like structure originates near the base of the falls. It aids in directing insects towards the nectaries and reproductive parts inside the bloom. Bearded irises get their name from this signature trait.
Hafts
The widened area at the base of the petals where they attach to the stem is called the haft. These may be decorated with delicate lines and veining.
Signal Patch
Some beardless iris varieties feature a colorful patch called a signal that replaces the beard on the falls.
Spathe
This papery bract emerges first, surrounding and protecting the developing iris bud. It dries and withers as the bud enlarges.
Spur
A short projection from the base of the sepal. Some irises have a long perianth tube in place of a stem, and the spur protrudes from that.
This covers the major structural components of a typical iris flower. There are also cultivated varieties that exhibit unique embellishments like flounces, spoons and horns extending from the petals and beards. Now that you’re acquainted with the anatomy of an iris, you can better understand how this exquisite flower functions and appreciate the nuances that set apart different iris species and hybrids.
How to hand pollinate Irises. Iris flower anatomy, pollination technique and seed pod development
FAQ
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