Not to be wishy-washy about it, but the concepts represented by some of these words are a bit fuzzy around the edges and tend to bleed into each other. Thomas the Rhymer's quotation from the American Heritage Dictionary seems to give some reasonable distinctions. The Merriam-Webster Dictionary is almost identical.

The melody of the Star-Spangled Banner accommodates quite a number of sets of words--including (mildly squeezing a couple of syllables in one line) Wildwood Flower. Try it. Feel free.   

Don Firth