Bamboo:

A symbol for longevity (it's always got green shoots) as well as strength and grace (it bends readily but doesn't break easily). In Chinese philosophy the straight stem of bamboo symbolizes the path towards enlightenment, the segments of the stem being the steps along the way.
Carnation:

A symbol of betrothal or engagement. In China, a carnation is a symbol of marriage.
Chrysanthemum:

The national symbol of Japan, 'mums are a symbol for long

Clover leaf:

The three divided leaves of clover represent the Christian Holy Trinity of God the Father, Christ the Son, and the Holy Spirit. Four-leafed clovers represent luck.
Daisy:

The most basic of flowers, a white daisy is a symbol of innocence.
Deadly nightshade:

A highly poisonous plant (Atropa belladonna) with purple bell flowers and small black berries. A symbol of deception, danger, and death.
Forget-me-not:

A low-growing plant (Myosotis) with small, usually blue flowers . As the common name suggests, a symbol of a plea for remembrance. "Forget me not" are supposed to have been the last words of young man who fell into a river and drowned while picking these flowers for his lover.
Honeysuckle:

A less-common symbol of love. Also of generosity.
Iris:

Associated with death as Iris was a Greek goddess of the rainbow, which she used to travel down to earth with messages from the gods and to transport women's souls to the underworld. The three upright petals and three drooping sepals are symbols for faith, valor, and wisdom.
Jasmine:

This strongly scented, white flower is used as a Hindu symbol for love.
Juniper:

Symbolizes chastity (because juniper berries are protected by the tree's thorny leaves), Christ (an association with the crown of thorns place on the head of Christ), and eternity (juniper wood is supposedly never attacked by bugs or worms).
Lily:

Symbolizes purity, chastity, and innocence. White lilies represent the purity of the Virgin Mary. The Angel Gabriel was often painted presenting Mary with a white lily when he announced to her that she would give birth to the Son of God.
Lotus:

A common symbol in Asian art, the lotus symbolizes birth and rebirth through the fact that the petals open when the sun comes out and close when the sun sets. Also a symbol for fertility, creation, and purity. The long stem symbolizes our connection to our origins, while the flower represents the enlightenment to which we aspire.
Mistletoe:

Standing under the mistletoe at Christmas gives anyone the opportunity to kiss you.
Orchid:

A symbol of perfection. The spots on an orchid sometimes represent the blood of Christ.
Poppy:

A symbol of death. Red poppies are a symbol of Remembrance Day (11 November), which commemorates the dead of the First and Second World Wars.
Rose:

To symbolize love and passion, use red roses. For virginity and purity use white roses. To symbolize jealousy and infidelity, use yellow roses. In Catholicism, red roses are a symbol of the Virgin Mary.

Rosemary:

Included in funeral wreaths as a symbol of remembrance and in wedding bouquets as a symbol for fidelity. It's said that if you touch a lover with a sprig of rosemary, they'll be faithful.
Sunflowers:

As a flower which blindly follows the sun, sunflowers have become a symbol of infatuation or foolish passion.
Thistle:

A thorny plant with a beautiful flower, the national symbol of Scotland. It's thorns symbolize both evil and protection. In Christianity it represents the suffering of Christ.
Violet:

Symbolize faithfulness, humility, and chastity.

Symbolism and the use of Flowers and their meaning
Many flowers have important symbolic meanings in Western culture. The practice of assigning meanings to flowers is known as floriography.

Some of the more common examples include:
Red roses are given as a symbol of love, beauty, and passion.
Poppies are a symbol of consolation in time of death. In the UK, New Zealand, Australia and Canada, red poppies are worn to commemorate soldiers who have died in times of war.
Irises/Lily are used in burials as a symbol referring to "resurrection/life". It is also associated with stars (sun) and its petals blooming/shining.
Daisies are a symbol of innocence.
Flowers within art are also representative of the female genitalia, as seen in the works of artists such as Georgia O'Keefe, Imogen Cunningham, Veronica Ruiz de Velasco, and Judy Chicago, and in fact in Asian and western classical art. Many cultures around the world have a marked tendency to associate flowers with femininity.
The great variety of delicate and beautiful flowers has inspired the works of numerous poets, especially from the 18th-19th century Romantic era. Famous examples include William Wordsworth's I Wandered Lonely as a Cloud and William Blake's Ah! Sun-Flower.
Because of their varied and colorful appearance, flowers have long been a favorite subject of visual artists as well. Some of the most celebrated paintings from well-known painters are of flowers, such as Van Gogh's sunflowers series or Monet's water lilies. Flowers are also dried, freeze dried and pressed in order to create permanent, three-dimensional pieces of flower art.
The Roman goddess of flowers, gardens, and the season of Spring is Flora. The Greek goddess of spring, flowers and nature is Chloris.
In Hindu mythology, flowers have a significant status. Vishnu, one of the three major gods in the Hindu system, is often depicted standing straight on a lotus flower. Apart from the association with Vishnu, the Hindu tradition also considers the lotus to have spiritual significance. For example, it figures in the Hindu stories of creation.