southern aster vs aster

southern aster and aster both are nouns.

Word	Noun	Adjective	Verb	Adverb
southern aster	Yes	No	No	No
aster	Yes	No	No	No

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

southern aster: a variety of aster, used to refer to both Eurybia hemispherica and Eurybia paludosa
aster: any of various chiefly fall-blooming herbs of the genus Aster with showy daisylike flowers

southern aster (noun)	aster (noun)
a variety of aster, used to refer to both Eurybia hemispherica and Eurybia paludosa	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