Rosa - Rosaceae - roses, rose hips

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• published: 09 Feb 2015
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A rose is a woody perennial of the genus Rosa, within the family Rosaceae. There are over 100 species and thousands of cultivars. They form a group of plants that can be erect shrubs, climbing or trailing with stems that are often armed with sharp prickles. Flowers vary in size and shape and are usually large and showy, in colours ranging from white through yellows and reds. Most species are native to Asia, with smaller numbers native to Europe, North America, and northwest Africa. Species, cultivars and hybrids are all widely grown for their beauty and often are fragrant. Rose plants range in size from compact, miniature roses, to climbers that can reach seven meters in height. Different species hybridize easily, and this has been used in the development of the wide range of garden roses. The leaves are borne alternately on the stem. Leaflets usually have a serrated margin, and often a few small prickles on the underside of the stem. Most roses are deciduous but a few (particularly from South east Asia) are evergreen or nearly so. The flowers of most species have five petals, with the exception of Rosa sericea, which usually has only four. Each petal is divided into two distinct lobes and is usually white or pink, though in a few species yellow or red. Beneath the petals are five sepals (or in the case of some Rosa sericea, four). There are multiple superior ovaries that develop into achenes. Roses are insect-pollinated in nature. The aggregate fruit of the rose is a berry-like structure called a rose hip. Many of the domestic cultivars do not produce hips, as the flowers are so tightly petalled that they do not provide access for pollination. 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, the hypanthium, which contains 5–160 "seeds" (technically dry single-seeded fruits called 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. Rose hips are occasionally made into jam, jelly, marmalade, and soup or are brewed for tea. They are also pressed and filtered to make rose hip syrup. Rose hips are also used to produce Rose hip seed oil. 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. While the sharp objects along a rose stem are commonly called "thorns", they are technically prickles — outgrowths of the epidermis (the outer layer of tissue of the stem). (True thorns, as produced by e.g. Citrus or Pyracantha, are modified stems, which always originate at a node and which have nodes and internodes along the length of the thorn itself.) Rose prickles 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 Rosa pimpinellifolia have densely packed straight prickles. Despite the presence of prickles, roses are frequently browsed by deer. 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. Rose water has a very distinctive flavour and is used heavily in Persian and Middle Eastern cuisine—especially in sweets such as nougat, gumdrops, raahat and baklava. Rose petals or flower buds are sometimes used to flavour ordinary tea, or combined with other herbs to make herbal teas. In France there is much use of rose syrup, most commonly made from an extract of rose petals. In the United States, French rose syrup is used to make rose scones and marshmallows. http://en.wikipedia.org/wiki/Rose