Are you talented enough to diagram this sentence?

[Karon]

What part of speech is pretty in the following sentence?

The flower is pretty.

Is pretty an adjective? I believe it is but may be wrong, can you help me? If so, is it a special kind of adjective with a specific name?

[Tdol]

It's an adjective. If you like, you could call it a predicative adjective:
http://www.usingenglish.com/glossary...adjective.html

[durianman]

could you write:

"The flower is pretty pretty."

Then pretty would be used as an adverb followed by the predicative adjective?

[Tdol]

You could if you wanted to.