althea vs marsh mallow

althea and marsh mallow both are nouns.

Word	Noun	Adjective	Verb	Adverb
althea	Yes	No	No	No
marsh mallow	Yes	No	No	No

As nouns, marsh mallow is a hyponym of althea; that is, marsh mallow is a word with a more specific, narrower meaning than althea:

althea: any of various plants of the genus Althaea; similar to but having smaller flowers than genus Alcea
marsh mallow: European perennial plant naturalized in United States having triangular ovate leaves and lilac-pink flowers

Other hyponyms of althea include Althea officinalis, white mallow.

althea (noun)	marsh mallow (noun)
any of various plants of the genus Althaea; similar to but having smaller flowers than genus Alcea	European perennial plant naturalized in United States having triangular ovate leaves and lilac-pink flowers