pistia vs water lettuce

pistia and water lettuce both are nouns.

Word	Noun	Adjective	Verb	Adverb
pistia	Yes	No	No	No
water lettuce	Yes	No	No	No

As nouns, pistia and water lettuce are synonyms defined as:

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

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

pistia (noun)	water lettuce (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