Science Fair Project Encyclopedia
About 100, see text
U. of Illinois 2002-05-29
There are more than a hundred species of wild roses, all from the northern hemisphere and mostly from temperate regions. 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 of most species 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) and Rugosa Rose (Rosa rugosa), are 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 or prickles. 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. Roses are also used as food plants by the larvae of some Lepidoptera species including Common Marbled Carpet.
The name originates from Persian *vrda- via Greek rhodon "rose" (Aeolic wrodon).
Some representative rose species (for more information, see the expanded List of Rose species).
- Rosa canina - Dog Rose, Briar Bush
- Rosa dumalis - Glaucous Dog Rose
- Rosa eglanteria (syn. R. rubiginosa) - Eglantine, Sweet Brier
- Rosa gigantea (syn. R. x odorata gigantea)
- Rosa glauca (syn. R. rubrifolia) - Redleaf Rose
- Rosa laevigata (syn. R. sinica) - Cherokee Rose, Camellia Rose, Mardan Rose
- Rosa multiflora - Multiflora Rose
- Rosa persica (syn. Hulthemia persica, R. simplicifolia)
- Rosa roxburghii - Chestnut Rose, Burr Rose
- Rosa rugosa - Rugosa Rose, Japanese Rose
- Rosa stellata - Gooseberry Rose, Sacramento Rose
- Rosa virginiana (syn. R. lucida) - Virginia Rose
Roses in cultivation
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:
- Wild Roses - The wild roses includes the species listed above and some of their hybrids.
- Old Garden Roses - Most old garden roses are classified into one of the following (ordered by approximate age - oldest first):
- Alba - Literally "white roses", derived from R. arvensis and the closely allied R. alba. These are some of the oldest garden roses, probably brought to Britain by the Romans. Once-flowering. Examples: 'Semi-plena', 'White Rose of York'
- Gallica - The Gallica roses have been developed from R. gallica which is a native of central and southern Europe. They flower once in the summer. Examples: 'Cardinal de Richelieu', 'Charles de Mills', 'Rosa Mundi' (R. gallica versicolor)
- Damask - Robert de Brie is given credit for bringing them from Persia to Europe sometime between 1254 and 1276. Summer Damasks (crosses between Gallica roses and R. phoenicea) bloom once in summer. Autumn Damasks (Gallicas crossed with R. moschata) bloom later, in the autumn. Examples: 'Ispahan', 'Madame Hardy'
- Centifolia (or Provence) - These roses, raised in the seventeenth century in the Netherlands, are named for their "one hundred" petals. Once-flowering. Examples: 'Centifolia', 'Paul Ricault'
- Moss - Closely related to the centifolias, these have a mossy excrescence on the stems and sepals. Once-flowering. Example: 'Comtesse de Murinais', 'Old Pink Moss'
- China - The China roses brought with them an amazing ability to bloom repeatedly throughout the summer and into late autumn. Four china roses ('Slater's Crimson China', 1792; 'Parsons' Pink China', 1793; 'Hume's Blush China', 1809; and 'Parks' Yellow Tea Scented China', 1824) were brought to Europe in the late eighteenth and nineteenth centuries which brought about the creation of the repeat flowering old garden roses and later the modern garden roses. Examples: 'Old Blush China', 'Mutabilis'
- Portland - These are named after the Duchess of Portland who received (from Italy in 1800) a rose then known as R. paestana or 'Scarlet Four Seasons' Rose' (now known simply as 'The Portland Rose'). This group was developed from that rose. Repeat-flowering. Example: 'James Veitch', 'Rose de Rescht', 'The Portland Rose'
- Bourbon - They originated on l'Île de Bourbon (now called Réunion). Probably the result of a cross between the Autumn Damask and the 'Old Blush China'. Introduced in France in 1823. Repeat-flowering. Examples: 'Louise Odier', 'Mme. Pierre Oger', 'Zéphirine Drouhin'
- Hybrid Perpetual - The dominant class of roses in Victorian England, they were derived to a great extent from the Bourbons. Repeat-flowering. Examples: 'Ferdinand Pichard', 'Reine Des Violettes'
- Tea - The result of crossing two of the original China Roses ('Hume's Blush China' and 'Parks' Yellow Tea Scented China') with various Bourbons and Noisette roses. Somewhat more tender than other old garden roses (most likely because of R. gigantea in the ancestry of the Parks rose), teas are repeat-flowering roses although their fragrance is not always a tea scent. Example: 'Lady Hillingdon'
- Miscellaneous - There are also a few smaller classes (such as Scots, Sweet Brier) and some climbing classes of old roses (including Ayrshire, Climbing China, Laevigata, Sempervirens, Noisette, Boursault, Climbing Tea, and Climbing Bourbon). Those classes with both climbing and shrub forms are often grouped together.
- Modern Garden Roses - Classification of modern roses can be quite confusing because many modern roses have old garden roses in their ancestry and their form varies so much. The classifications tend to be by growth and flowering characteristics, such as "large-flowered shrub", "recurrent, large-flowered shrub", "cluster-flowered", "rambler recurrent", or "ground-cover non-recurrent". Many of the most popular modern cultivars can however be assigned to one of these two groups:
- Hybrid Tea - The favourite florist's rose, with typically one to at most five or six large flowers per stem, the flower with numerous tightly arranged petals with reflexed tips (see photo, right). They are favoured in small gardens in formal situations, and for buttonhole roses.
- Floribunda - Flowers often smaller, in large clusters of ten or more (often many more) on each stem. These tend to give a more prominent display from a distance, so are more often used in large bedding schemes in public parks and similar spaces.
Roses and culture
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).
Roses come in a variety of colors, each with a different symbolic meaning:
- Red: love
- Pink: grace
- Dark Pink: gratitude
- Light Pink: admiration, sympathy
- White: innocence, secrecy (see also: White Rose German resistance movement)
- Yellow: dying love or platonic love
- Orange: passion
- Burgundy: beauty
- Blue: mystery (traditionally created by dyeing white roses, after 15 years of research, genetically modified blue roses were created by a partnership of Australian company Florigene , and Japanese company Suntory in 2004)
Roses in art
Roses named after famous people
- What's in a name? That which we call a rose/By any other name would smell as sweet. – William Shakespeare, Romeo and Juliet act II, sc. ii
- Hearts starve as well as bodies; give us bread, but give us roses. - James Oppenheim, "Bread and Roses"
- Rose is a rose is a rose is a rose. – Gertrude Stein, Sacred Emily (1913), a poem included in Geography and Plays.
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 Persia (the word Rose itself is from Persian) then spread through Arabia and India, but nowadays about 70% to 80% of production is in the 'Valley of Roses' near Kazanluk in Bulgaria, with some production in Qamsar in Iran and Germany. The Kaaba in Mecca is annually washed by the Iranian rose water from Qamsar. In Bulgaria, Iran and Germany 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.
- HelpMeFind Roses A great resource if you are looking for information on particular roses. It gets significant contributions of information and pictures from the community.
- Just Our Pictures of Roses A large database of rose pictures sorted by colour, type and alphabetically.
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