water lettuce vs Pistia stratiotes

water lettuce and Pistia stratiotes both are nouns.

Word	Noun	Adjective	Verb	Adverb
water lettuce	Yes	No	No	No
Pistia stratiotes	Yes	No	No	No

As nouns, water lettuce and Pistia stratiotes are synonyms defined as:

water lettuce and Pistia stratiotes: pantropical floating plant forming a rosette of wedge-shaped leaves; a widespread weed in rivers and lakes

Other synonyms of water lettuce include pistia, Pistia stratoites, water cabbage.

water lettuce (noun)	Pistia stratiotes (noun)
pantropical floating plant forming a rosette of wedge-shaped leaves; a widespread weed in rivers and lakes	pantropical floating plant forming a rosette of wedge-shaped leaves; a widespread weed in rivers and lakes