fountain grass vs Pennisetum ruppelii

fountain grass and Pennisetum ruppelii both are nouns.

Word	Noun	Adjective	Verb	Adverb
fountain grass	Yes	No	No	No
Pennisetum ruppelii	Yes	No	No	No

As nouns, fountain grass and Pennisetum ruppelii are synonyms defined as:

fountain grass and Pennisetum ruppelii: tall perennial ornamental grass with long nodding flower plumes of tropical Africa and Asia

Other synonyms of fountain grass include Pennisetum setaceum.

fountain grass (noun)	Pennisetum ruppelii (noun)
tall perennial ornamental grass with long nodding flower plumes of tropical Africa and Asia	tall perennial ornamental grass with long nodding flower plumes of tropical Africa and Asia