pearl-weed vs pearlweed

pearl-weed and pearlweed both are nouns.

Word	Noun	Adjective	Verb	Adverb
pearl-weed	Yes	No	No	No
pearlweed	Yes	No	No	No

As nouns, pearl-weed and pearlweed are synonyms defined as:

pearl-weed and pearlweed: any of various low-growing plants of the genus Sagina having small spherical flowers resembling pearls

Other synonyms of pearl-weed include pearlwort.

pearl-weed (noun)	pearlweed (noun)
any of various low-growing plants of the genus Sagina having small spherical flowers resembling pearls	any of various low-growing plants of the genus Sagina having small spherical flowers resembling pearls