snake-head vs genus Chelone

snake-head and genus Chelone both are nouns.

Word	Noun	Adjective	Verb	Adverb
snake-head	Yes	No	No	No
genus Chelone	Yes	No	No	No

snake-head (noun)	genus Chelone (noun)
showy perennial of marshlands of eastern and central North America having waxy lanceolate leaves and flower with lower part creamy white and upper parts pale pink to deep purple	herbaceous perennials: shellflower