perianth vs natural covering

perianth and natural covering both are nouns.

Word	Noun	Adjective	Verb	Adverb
perianth	Yes	No	No	No
natural covering	Yes	No	No	No

As nouns, natural covering is a hypernym of perianth; that is, natural covering is a word with a broader meaning than perianth:

perianth: collective term for the outer parts of a flower consisting of the calyx and corolla and enclosing the stamens and pistils
natural covering: a natural object that covers or envelops

Other hypernyms of perianth include cover, covering, plant organ.

perianth (noun)	natural covering (noun)
collective term for the outer parts of a flower consisting of the calyx and corolla and enclosing the stamens and pistils	a natural object that covers or envelops