plant life vs monocotyledonous

plant life is a noun but monocotyledonous is not a noun.

Word	Noun	Adjective	Verb	Adverb
plant life	Yes	No	No	No
monocotyledonous	No	Yes	No	No

plant life (noun)	monocotyledonous (noun)
(botany) a living organism lacking the power of locomotion

plant life (adjective)	monocotyledonous (adjective)
	(of a flowering plant) having a single cotyledon in the seed as in grasses and lilies