Rose
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- For other uses, see Rose (disambiguation).
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RoseFrom open-encyclopedia.com - the free encyclopedia.
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There are more than a hundred species of wild roses, mostly from the temperate northern hemisphere. The species form a group of generally thorny shrubs or climbers, and sometimes trailing plants, reaching 2-5 m tall, rarely reaching as high as 20 m by climbing over other plants.
The leaves are 5-15 cm long, pinnate, with (3-) 5-9 (-13) leaflets and basal stipules; the leaflets have a serrated margin, and often a few small thorns on the underside of the stem. The vast majority of roses are deciduous, but a few (particularly in southeast Asia) are evergreen or nearly so.
The flowers have five petals, usually white or pink, in a few species yellow or red. The ovary is inferior, developing below the petals and sepals.
The fruit of the rose is a berry-like structure called a rose hip. The hips of most species are red, but a few (e.g. Rosa pimpinellifolia) have dark purple to black hips. Each hip comprises an outer fleshy layer, and inside containing 5-25 seeds (technically achenes) embedded in a matrix of fine, but stiff, hairs. Rose hips of some species, especially the Dog Rose Rosa canina, very rich in vitamin C, among the richest sources of any plant. The hips are eaten by fruit-eating birds such as thrushes and waxwings, which then disperse the seeds in their droppings. Some birds, particularly finches, also eat the seeds.
Most roses have thorns. The thorns are typically sickle-shaped hooks, which aid the rose in hanging onto other vegetation when growing over it. Some species such as Rosa rugosa and R. pimpinellifolia though have densely packed straight spines, probably an adaptation to reduce browsing by animals, but also possibly an adaptation to trap wind-blown sand and so reduce erosion and protect their roots (both the two species cited grow naturally on coastal sand dunes). Despite the presence of the thorns, roses are frequently heavily browsed by deer. A few species of roses only have vestigial thorns that have no points.
Roses are subject to several diseases. The most serious is rose rust (Phragmidium tuberculatum), a species of Rust fungus, which can defoliate the plant. Rather commoner, but slightly less debilitating, is rose black spot, caused by the fungus Diplocarpon rosae, which makes circular black spots on the leaves in summer.
| R. alba 'Semi-plena' |
| Rose 'Zépherine Drouhin' |
| Rose 'Sarah van Fleet' |
| A modern Hybrid Tea rose |
Roses are one of the most popular garden shrubs, and are also among the most common flowers sold by florists. Roses are of great economic importance both as a crop for florists' use and for use in perfume.
An enormous number (several thousands) of rose hybrids and cultivars have been bred and selected for garden use, mostly double-flowered with many or all of the stamens mutated into additional petals. Twentieth-century rose breeders generally emphasized size and color, producing large, attractive blooms with little or no scent. Many wild and "old-fashioned" roses, by contrast, have a strong sweet scent. A few cultivars, such as the Lady Banks rose have been selected for having no thorns. Some nurseries, such as Harkness Roses, are almost entirely devoted to breeding and selling roses, stocking few other plants.
The hips are sometimes eaten, mainly for their vitamin C content. They are usually pressed and filtered to make rose hip syrup, as the fine hairs surrounding the seeds are unpleasant to eat (resembling itching powder). They can also be used to make herbal tea, jam, jelly and marmalade.
There is no single system of classification for garden roses. In general, however, roses are placed in one of three main groups:
Roses are ancient symbols of love and beauty. The rose was sacred to a number of goddesses, and is often used as a symbol of the Virgin Mary. Roses are so important that the word means pink or red in a variety of languages (such as Romance languages and Greek).
The rose is the national flower of England, the provincial flower of Alberta (the wild rose), and the state flower of North Dakota.
A red rose (often held in a hand) is also a symbol of socialism or social democracy; it is also used as a symbol by the United Kingdom Labour Party.
Roses come in a variety of colors, each with a different symbolic meaning:
Roses are commonly portrayed by artists. The French artist Pierre-Joseph Redouté produced some of the most detaled paintings of roses.
Rose perfumes are made from attar of roses or rose oil, which is a mixture of volatile essential oils obtained by steam-distilling the crushed petals of roses. The technique originated in Arabia (the word attar is from Arabic), then spread through Persia (now Iran) and India, but nowadays about 70% to 80% of production is in the 'Valley of Roses' near Kazanluk in Bulgaria, with some production in Germany. In these two countries, damask roses (Rosa damascena 'Trigintipetala') are used. In the French rose oil industry Rosa centifolia is used. The oil, pale yellow or yellow-grey in colour, is sometimes called 'Rose Absolute' oil to distinguish it from diluted versions. The weight of oil extracted is about one three-thousandth to one six-thousandth of the weight of the flowers - for example, about 2,000 flowers are required to produce one gramme of oil.
The main constituents of attar of roses are the fragrant alcohols geraniol, which has the empirical formula C10H18O and the structural formula CH3.C[CH3]:CH.CH2.CH2.C[CH3]:CH.CH2OH and l-citronellol; and rose camphor, an odourless paraffin.
da:Rose (Rosa)
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ja:バラ
ms:Bunga ros
nl:Roos (plant)
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zh:玫瑰
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