stomatal vs stoma

stomatal is not a noun while stoma is a noun.

Word	Noun	Adjective	Verb	Adverb
stomatal	No	Yes	No	No
stoma	Yes	No	No	No

stomatal (noun)	stoma (noun)
	a mouth or mouthlike opening (especially one created by surgery on the surface of the body to create an opening to an internal organ)
	a minute epidermal pore in a leaf or stem through which gases and water vapor can pass

stomatal (adjective)	stoma (adjective)
relating to or constituting plant stomata
relating to or of the nature of or having a mouth or mouthlike opening