feathertop vs feathertop grass

feathertop and feathertop grass both are nouns.

Word	Noun	Adjective	Verb	Adverb
feathertop	Yes	No	No	No
feathertop grass	Yes	No	No	No

As nouns, feathertop and feathertop grass are synonyms defined as:

feathertop and feathertop grass: northeastern tropical African plant having feathery panicles

Other synonyms of feathertop include Pennistum villosum.

feathertop (noun)	feathertop grass (noun)
northeastern tropical African plant having feathery panicles	northeastern tropical African plant having feathery panicles
a variety of reed grass