Rose
From Wikipedia, the free encyclopedia
A
rose is a
perennial plant of the
genus Rosa, within the family
Rosaceae. There are over 100 species. They form a group of erect shrubs, and climbing or trailing plants, with stems that are often armed with sharp
prickles. Flowers are large and showy, in a number of colours 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 fragrance. Rose plants range in size from compact, miniature roses, to climbers that can reach 7 meters in height. Species from different parts of the world easily hybridize, which has given rise to the many types of garden roses.
[1]
The name
rose comes from French, itself from Latin,
rosa, which was borrowed from
Oscan, from Greek
ρόδιόν rhodion (
Aeolic υρόδιόν wrodion), from
Old Persian 𐎹𐎢𐎼𐎭𐎡 wurdi "flower" (cf.
Avest.
warda,
Sogdian ward,
Parthian wâr).
[2][3]
Botany
The
leaves are borne alternately on the stem. In most species they are 5–15 centimetres long,
pinnate, with (3–) 5–9 (–13) leaflets and basal stipules; the 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). These may be long enough to be visible when viewed from above and appear as green points alternating with the rounded petals. The ovary is inferior, developing below the petals and sepals. 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. 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.
Rose thorns are actually prickles - outgrowths of the epidermis.
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 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 of these species grow naturally on
coastal sand dunes). Despite the presence of prickles, roses are frequently browsed by
deer. A few species of roses have only vestigial prickles that have no points.
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