Arundo donax vs giant reed

Arundo donax and giant reed both are nouns.

Word	Noun	Adjective	Verb	Adverb
Arundo donax	Yes	No	No	No
giant reed	Yes	No	No	No

As nouns, Arundo donax and giant reed are synonyms defined as:

Arundo donax and giant reed: large rhizomatous perennial grasses found by riversides and in ditches having jointed stems and large grey-white feathery panicles

Arundo donax (noun)	giant reed (noun)
large rhizomatous perennial grasses found by riversides and in ditches having jointed stems and large grey-white feathery panicles	large rhizomatous perennial grasses found by riversides and in ditches having jointed stems and large grey-white feathery panicles