Rose

A rose (/ˈroʊz/) is a woody perennial flowering plant of the genus Rosa, in 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 name rose comes from French, itself from Latin rosa, which was perhaps borrowed from Oscan, from Greek ρόδον rhódon (Aeolic βρόδον wródon), itself borrowed from Old Persian wrd- (wurdi), related to Avestan varəδa, Sogdian ward, Parthian wâr.

Rose (mathematics)

In mathematics, a rose or rhodonea curve is a sinusoid plotted in polar coordinates.

General overview

Up to similarity, these curves can all be expressed by a polar equation of the form

or, alternatively, as a pair of Cartesian parametric equations of the form

If k is an integer, the curve will be rose-shaped with

Where k is even, the entire graph of the rose will be traced out exactly once when the value of theta,θ changes from 0 to 2π. When k is odd, this will happen on the interval between 0 and π. (More generally, this will happen on any interval of length 2π for k even, and π for k odd.)

If k is a half-integer (e.g. 1/2, 3/2, 5/2), the curve will be rose-shaped with 4k petals.

If k can be expressed as n±1/6, where n is a nonzero integer, the curve will be rose-shaped with 12k petals.

If k can be expressed as n/3, where n is an integer not divisible by 3, the curve will be rose-shaped with n petals if n is odd and 2n petals if n is even.

Rose (symbolism)

Roses have been long used as symbols in a number of societies. Roses are ancient symbols of love and beauty. "Rose" means pink or red in a variety of languages (such as the Romance languages and Greek).

The Classical Era

The rose was sacred to a number of goddesses including Isis, whose rose appears in the late classical allegorical novel The Golden Ass as "the sweet Rose of reason and virtue" that saves the hero from his bewitched life in the form of a donkey. The ancient Greeks and Romans identified the rose with the goddess of love, Aphrodite (Greek name) and Venus (Roman name).

In Rome a wild rose would be placed on the door of a room where secret or confidential matters were discussed. The phrase sub rosa, or "under the rose", means to keep a secret — derived from this ancient Roman practice.

Islam and Sufism

The cultivation of geometrical gardens, in which the rose has often held pride of place, has a long history in Iran and surrounding lands. In the lyric ghazal, it is the beauty of the rose that provokes the longing song of the nightingale - an image prominent, for example, in the poems of Hafez.