vernal iris vs dwarf iris

vernal iris and dwarf iris both are nouns.

Word	Noun	Adjective	Verb	Adverb
vernal iris	Yes	No	No	No
dwarf iris	Yes	No	No	No

As nouns, vernal iris and dwarf iris are synonyms defined as:

vernal iris and dwarf iris: low-growing spring-flowering American iris with bright blue-lilac flowers

Other synonyms of vernal iris include Iris verna.

vernal iris (noun)	dwarf iris (noun)
low-growing spring-flowering American iris with bright blue-lilac flowers	low-growing spring-flowering American iris with bright blue-lilac flowers
	low-growing summer-flowering iris of northeastern United States