vegetable oyster vs salsify

vegetable oyster and salsify both are nouns.

Word	Noun	Adjective	Verb	Adverb
vegetable oyster	Yes	No	No	No
salsify	Yes	No	No	No

As nouns, salsify is a hypernym of vegetable oyster; that is, salsify is a word with a broader meaning than vegetable oyster:

As nouns, vegetable oyster and salsify are synonyms defined as:

vegetable oyster and salsify: Mediterranean biennial herb with long-stemmed heads of purple ray flowers and milky sap and long edible root; naturalized throughout United States

Other synonyms of vegetable oyster include oyster plant, Tragopogon porrifolius.

vegetable oyster (noun)	salsify (noun)
long white salsify	either of two long roots eaten cooked
Mediterranean biennial herb with long-stemmed heads of purple ray flowers and milky sap and long edible root; naturalized throughout United States	Mediterranean biennial herb with long-stemmed heads of purple ray flowers and milky sap and long edible root; naturalized throughout United States
	edible root of the salsify plant