stonecress vs stone cress

stonecress and stone cress both are nouns.

Word	Noun	Adjective	Verb	Adverb
stonecress	Yes	No	No	No
stone cress	Yes	No	No	No

As nouns, stonecress and stone cress are synonyms defined as:

stonecress and stone cress: any Old World herb of the genus Aethionema; native of sunny limestone habitats

stonecress (noun)	stone cress (noun)
any Old World herb of the genus Aethionema; native of sunny limestone habitats	any Old World herb of the genus Aethionema; native of sunny limestone habitats