water dragon vs Saururus cernuus

water dragon and Saururus cernuus both are nouns.

Word	Noun	Adjective	Verb	Adverb
water dragon	Yes	No	No	No
Saururus cernuus	Yes	No	No	No

As nouns, water dragon and Saururus cernuus are synonyms defined as:

water dragon and Saururus cernuus: North American herbaceous perennial of wet places having slender curled racemes of small white flowers

Other synonyms of water dragon include lizard's-tail, swamp lily.

water dragon (noun)	Saururus cernuus (noun)
swamp plant of Europe and North America having bright yellow flowers resembling buttercups	North American herbaceous perennial of wet places having slender curled racemes of small white flowers
North American herbaceous perennial of wet places having slender curled racemes of small white flowers