Plant Life Around: Nettle

Nettle is a wild herbaceous plant covered with tiny hollow hairs that inject irritating chemicals when touched.  Urtica dioica is its scientific name. 

The word is often used in literature because it symbolises pain, difficulty or unpleasant experience. 

Literal Examples:

He brushed against a nettle and his hand began to sting.

Figurative example:

To grasp the nettle means to deal boldly with a difficult problem instead of avoiding it.

Nettled means (adjective/verb)  irritated, annoyed, or provoked.

She was nettled by his rude remarks.

In Chapter 1 of Great Expectations, Dickens describe the escaped convict like this:

..... lamed by stones or flints and stung by nettles.

Here nettles are meant by literally, not figuratively.

The convict had been hiding and 

running through the country side.

He cut and bruised his feet on sharp flints, and he was stung by nettles growing in hedges and waste land.

He is also cold, hungry, soaked and wearing broken prison clothes 

Dickens piles up these details to show the convict's wretched physical condition.  The description makes him seem frightening at first, but it also evokes sympathy.

The phrase stung by nettles means that prickly hairs of the nettle had burned and irritated his skin, adding to his pain as he fled across the rough country side.