Honeysuckle (Lonicera periclymenum)

Honeysuckle by Trish Steel, CC BY-SA 2.0, via Wikimedia Commons

"And bid her steal into the pleached bower,

Where honeysuckles, ripen'd by the sun
Forbid the sun to enter."

- Much Ado About Nothing, Act III, Scene 1

Harebells and Bluebells

English Bluebell (Hyacinthoides non-scripta)

"I'll sweeten thy sad grave: thou shalt not lack

The flower that's like thy face, pale primrose, nor

The azured hare-bell, like thy veins."

- Cymbeline, Act IV, Scene 2

There is some debate as to what wildflower Shakespeare is referring to when he speaks of "the azured hare-bell". Some argue that he is referring to the English Bluebell (Hyacinthoides non-scripta), sometimes called the English Wild Hyacinth (Scilla nutans). However he may also be referring to the Campanula rotundifolia, which rather confusingly is also called the Harebell and Bluebell in different parts of the British Isles. 

Lilies in Shakespeare

Lily (Lilium candidum)

"To gild refilded gold, to paint the lily

...

Is wasteful and ridiculous excess."

- King John, Act IV, Scene 2

Ophelia's Flowers

Ophelia by Alexandre Cabanel, 1883

Ophelia's Bouquet

  
"There’s rosemary, that’s for remembrance. 
 Pray you, love, remember.
 And there is pansies, that’s for thoughts ...
There’s fennel for you, and columbines.

There’s rue for you, and here’s some for me. 
We may call it “herb of grace” o' Sundays.
- Oh, you must wear your rue with a difference.
There’s a daisy. I would give you some violets, 
But they withered all when my father died."

- Hamlet, Act IV, Scene 5