Pennisetum ruppelii vs fountain grass

Pennisetum ruppelii and fountain grass both are nouns.

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

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

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

Other synonyms of Pennisetum ruppelii include Pennisetum setaceum.

Pennisetum ruppelii (noun)	fountain grass (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