sea starwort vs aster

sea starwort and aster both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea starwort	Yes	No	No	No
aster	Yes	No	No	No

As nouns, aster is a hypernym of sea starwort; that is, aster is a word with a broader meaning than sea starwort:

sea starwort: a common European aster that grows in salt marshes
aster: any of various chiefly fall-blooming herbs of the genus Aster with showy daisylike flowers

sea starwort (noun)	aster (noun)
a common European aster that grows in salt marshes	star-shaped structure formed in the cytoplasm of a cell having fibers like rays that surround the centrosome during mitosis
	any of various chiefly fall-blooming herbs of the genus Aster with showy daisylike flowers