kinds of flowers

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<p>FlowerIINTRODUCTION</p> <p>IrisTriggered mainly by the shortening periods of darkness during spring, flower buds open to display brightly colored petals that attract insects seeking nectar. Once a flower has been pollinated, its petals shrivel and drop off.Oxford Scientific FilmsFlower, reproductive organ of most seed-bearing plants. Flowers carry out the multiple roles of sexual reproduction, seed development, and fruit production. Many plants produce highly visible flowers that have a distinctive size, color, or fragrance. Almost everyone is familiar with beautiful flowers such as the blossoms of roses, orchids, and tulips. But many plantsincluding oaks, beeches, maples, and grasseshave small, green or gray flowers that typically go unnoticed. </p> <p>LilacThe common lilac is one of a group of deciduous trees and shrubs grown primarily for their extremely fragrant flowers. Originating in temperate Eurasia, the lilac is now cultivated in temperate regions of the world in sunny locations with thick, fertile, preferably alkaline soils.Stuart Bebb/Oxford Scientific FilmsWhether eye-catching or inconspicuous, all flowers produce the male or female sex cells required for sexual reproduction. Flowers are also the site of fertilization, which is the union of a male and female sex cell to produce a fertilized egg. The fertilized egg then develops into an embryonic (immature) plant, which forms part of the developing seed. Neighboring structures of the flower enclose the seed and mature into a fruit. </p> <p>Water LilyWater lilies usually float on the surface of quiet waters, with the stalk reaching down to the earth. Some varieties, however, grow completely under water, even producing their flowers and fruits while submerged.Michael P. Gadomski/Bruce Coleman, Inc.Botanists estimate that there are more than 240,000 species of flowering plants. However, flowering plants are not the only seed-producing plants. Pines, firs, and cycads are among the few hundred plants that bear their seeds on the surface of cones, rather than within a fruit. Botanists call the cone-bearing plants gymnosperms, which means naked seeds; they refer to flowering plants as angiosperms, which means enclosed seeds. </p> <p>BougainvilleaThe showy display of bougainvillea plants is due to three large, brightly colored bracts that surround each inconspicuous flower. Many hybrids of bougainvillea have been cultivated for their ornamental value, including two varieties with multiple bract colors on a single plant.Dorling KindersleyFlowering plants are more widespread than any other group of plants. They bloom on every continent, from the bogs and marshes of the Arctic tundra to the barren soils of Antarctica. Deserts, grasslands, rainforests, and other biomes display distinctive flower species. Even streams, rivers, lakes, and swamps are home to many flowering plants. </p> <p>Lily of the ValleyThe Convallaria majalis, known as the lily of the valley, is a perennial herb found in Eurasia and eastern North America and is popular for shady gardens. A dichotomous plant, it has long-stalked oval leaves and a stem of several white flowers. These tiny, pungent, bell-shaped flowers are used in the manufacture of perfume.John Bova/Photo Researchers, Inc.In their diverse environments, flowers have evolved to become irreplaceable participants in the complex, interdependent communities of organisms that make up ecosystems. The seeds or fruits that flowers produce are food sources for many animals, large and small. In addition, many insects, bats, hummingbirds, and small mammals feed on nectar, a sweet liquid produced by many flowers, or on flower products known as pollen grains. The animals that eat flowers, seeds, and fruits are prey for other animalslizards, frogs, salamanders, and fish, for examplewhich in turn are devoured by yet other animals, such as owls and snakes. Thus, flowers provide a bountiful feast that sustains an intricate web of predators and prey (see Food Web).</p> <p>Jack-in-the-Pulpit plantArum is the common name for about 2,000 species of mostly herbaceous flowering plants, some of which have edible, starchy rootstocks. The jack-in-the-pulpit plant, a member of the arum family, shown here, was used as a food source for eastern Native Americans.Kerry T. Givens/Tom Stack and AssociatesFlowers play diverse roles in the lives of humans. Wildflowers of every hue brighten the landscape, and the attractive shapes and colors of cultivated flowers beautify homes, parks, and roadsides. The fleshy fruits that flowers produce, such as apples, grapes, strawberries, and oranges, are eaten worldwide, as are such hard-shelled fruits as pecans and other nuts. Flowers also produce wheat, rice, oats, and cornthe grains that are dietary mainstays throughout the world. People even eat unopened flowers, such as those of broccoli and cauliflower, which are popular vegetables. Natural dyes come from flowers, and fragrant flowers, such as jasmine and damask rose, are harvested for their oils and made into perfumes. Certain flowers, such as red clover blossoms, are collected for their medicinal properties, and edible flowers, such as nasturtiums, add color and flavor to a variety of dishes. Flowers also are used to symbolize emotions, as is evidenced by their use from ancient times in significant rituals, such as weddings and funerals. IIPARTS OF A FLOWER</p> <p>Parts of a FlowerAll flowers share several basic features. Sepals, protective coverings that are closed over the bud before it blooms, are the outermost flower parts. One step inward lie the petals, which serve to attract pollinators using both coloration and scent-producing glands. Inside the petals are the flower's sexual organs, the stamens and pistil. Each stamen, the pollen producing part of the flower, includes an anther and a filament. At the center of the flower is the pistil, composed of a stigma, a style, and an ovary. Within the ovary is a small cavity that contains the ovule, an egg-shaped structure that, when fertilized, eventually becomes a seed. Microsoft Corporation. All Rights Reserved.Flowers typically are composed of four parts, or whorls, arranged in concentric rings attached to the tip of the stem. From innermost to outermost, these whorls are the (1) pistil, (2) stamens, (3) petals, and (4) sepals. APistil</p> <p>Reproductive Parts of a FlowerWithin the petals are the reproductive parts of a flower: the stamens and the pistils. The stamens carry pollen-containing sacs called anthers (orange in this photograph). The sticky stigmas (green) at the tip of the pistils trap grains of pollen.George B. Diebold/CorbisThe innermost whorl, located in the center of the flower, is the female reproductive structure, or pistil. Often vase-shaped, the pistil consists of three parts: the stigma, the style, and the ovary. The stigma, a slightly flared and sticky structure at the top of the pistil, functions by trapping pollen grains, the structures that give rise to the sperm cells necessary for fertilization. The style is a narrow stalk that supports the stigma. The style rises from the ovary, a slightly swollen structure seated at the base of the flower. Depending on the species, the ovary contains one or more ovules, each of which holds one egg cell. After fertilization, the ovules develop into seeds, while the ovary enlarges into the fruit. If a flower has only one ovule, the fruit will contain one seed, as in a peach. The fruit of a flower with many ovules, such as a tomato, will have many seeds. An ovary that contains one or more ovules also is called a carpel, and a pistil may be composed of one to several carpels.BStamens</p> <p>The next whorl consists of the male reproductive structures, several to many stamens arranged around the pistil. A stamen consists of a slender stalk called the filament, which supports the anther, a tiny compartment where pollen forms. When a flower is still an immature, unopened bud, the filaments are short and serve to transport nutrients to the developing pollen. As the flower opens, the filaments lengthen and hold the anthers higher in the flower, where the pollen grains are more likely to be picked up by visiting animals, wind, or in the case of some aquatic plants, by water. The animals, wind, or water might then carry the pollen to the stigma of an appropriate flower. The placement of pollen on the stigma is called pollination. Pollination initiates the process of fertilization.CPetals</p> <p>Petals, the next whorl, surround the stamens and collectively are termed the corolla. Many petals have bright colors, which attract animals that carry out pollination, collectively termed pollinators. Three groups of pigmentsalone or in combinationproduce a veritable rainbow of petal colors: anthocyanins yield shades of violet, blue, and red; betalains create reds; and carotenoids produce yellows and orange. Petal color can be modified in several ways. Texture, for example, can play a role in the overall effecta smooth petal is shiny, while a rough one appears velvety. If cells inside the petal are filled with starch, they create a white layer that makes pigments appear brighter. Petals with flat air spaces between cells shimmer iridescently. In some flowers, the pigments form distinct patterns, invisible to humans but visible to bees, who can see ultraviolet light. Like the landing strips of an airport, these patterns, called nectar guides, direct bees to the nectar within the flower. Nectar is made in specialized glands located at or near the petals base. Some flowers secrete copious amounts of nectar and attract big pollinators with large appetites, such as bats. Other flowers, particularly those that depend on wind or water to transport their pollen, may secrete little or no nectar. The petals of many species also are the source of the fragrances that attract pollinators. In these species, the petals house tiny glands that produce essential, or volatile, oils that vaporize easily, often releasing a distinctive aroma. One flower can make dozens of different essential oils, which mingle to yield the flowers unique fragrance. DSepals</p> <p>Horse Chestnut Buds Starting to OpenSepals tightly enclose the pistil, stamens, and petals of a developing flower bud. The bud growing at the end of this horse chestnut bud is called a terminal bud.Oxford Scientific FilmsThe sepals, the outermost whorl, together are called the calyx. In the flower bud, the sepals tightly enclose and protect the petals, stamens, and pistil from rain or insects. The sepals unfurl as the flower opens and often resemble small green leaves at the flowers base. In some flowers, the sepals are colorful and work with the petals to attract pollinators. EVariations in Structure</p> <p>Zucchini PlantZucchini and many other squash plants feature pistillate flowers, or flowers with only female reproductive structures, and staminate flowers, those with only male reproductive structures, growing on the same plant. Plants of this type are called mooecious species. In dioecious species, such as date trees, staminate and pistillate flowers are found on different plants. Successful reproduction depends on male reproductive cells from the plant with the staminate flowers being transferred to the plant with the pistillate flowers.David Cavagnaro/Visuals UnlimitedLike virtually all forms in nature, flowers display many variations in their structure. Most flowers have all four whorlspistil, stamens, petals, and sepals. Botanists call these complete flowers. But some flowers are incomplete, meaning they lack one or more whorls. Incomplete flowers are most common in plants whose pollen is dispersed by the wind or water. Since these flowers do not need to attract pollinators, most have no petals, and some even lack sepals. Certain wind-pollinated flowers do have small sepals and petals that create eddies in the wind, directing pollen to swirl around and settle on the flower. In still other flowers, the petals and sepals are fused into structures called a floral tube.Flowers that lack either stamens or a pistil are said to be imperfect. The petal-like rays on the edge of a sunflower, for example, are actually tiny, imperfect flowers that lack stamens. Imperfect flowers can still function in sexual reproduction. A flower that lacks a pistil but has stamens produces pollen, and a flower with a pistil but no stamens provides ovules and can develop into fruits and seeds. Flowers that have only stamens are termed staminate, and flowers that have only a pistil are called pistillate.Although a single flower can be either staminate or pistillate, a plant species must have both to reproduce sexually. In some species with imperfect flowers, the staminate and pistillate flowers occur on the same plant. Such plants, known as monoecious species, include corn. The tassel at the top of the corn plant consists of hundreds of tiny staminate flowers, and the ears, which are located laterally on the stem, contain clusters of pistillate flowers. The silks of corn are very long styles leading to the ovaries, which, when ripe, form the kernels of corn. In dioecious speciessuch as date, willow, and hempstaminate and pistillate flowers are found on different plants. A date tree, for example, will develop male or female flowers but not both. In dioecious species, at least two plants, one bearing staminate flowers and one bearing pistillate flowers, are needed for pollination and fertilization.</p> <p>Types of InflorescencesSometimes flowers are grouped together in a cluster called an inflorescence. Each type of inflorescence is identified by the arrangement of flowers on a stalk. Microsoft Corporation. All Rights Reserved.Other variations are found in the types of stems that support flowers. In some species, flowers are attached to only one main stem, called the peduncle. In others, flowers are attached to smaller stems, called pedicels, that branch from the peduncle. The peduncle and pedicels orient a flower so that its pollinator can reach it. In the morning glory, for example, pedicels hold the flowers in a horizontal position. This enables their hummingbird pollinators to feed since they do not crawl into the flower as other pollinators do, but hover near the flower and lick the nectar with their long tongues. Scientists assign specific terms to the different flower and stem arrangements to assist in the precise identification of a flower. A plant with just one flower at the tip of the pedunclea tulip, for exampleis termed solitary. In a spike, such as sage, flowers are attached to the sides of the peduncle.Sometimes flowers are grouped together in a cluster called an inflorescence. In an indeterminate inflorescence, the lower flowers bloom first, and blooming proceeds over a period of days from the bottom to the top of the peduncle or pedicels. As long as light, water, temperature, and nutrients are favorable, the tip of the peduncle or pedicel continues to add new buds. There are several types of inde...</p>