lesser duckweed vs common duckweed

lesser duckweed and common duckweed both are nouns.

Word	Noun	Adjective	Verb	Adverb
lesser duckweed	Yes	No	No	No
common duckweed	Yes	No	No	No

As nouns, lesser duckweed and common duckweed are synonyms defined as:

lesser duckweed and common duckweed: of temperate regions except eastern Asia and Australia

Other synonyms of lesser duckweed include Lemna minor.

lesser duckweed (noun)	common duckweed (noun)
of temperate regions except eastern Asia and Australia	of temperate regions except eastern Asia and Australia