Flowers from Africa are now grown in Middle Eastern greenhouses and sold to markets in Europe and Asia
Middle Easter is a proper adjective for noun ”greenhouses.”
A proper adjective is actually a proper noun which is placed before a noun, where an adjective should be, in order to modify and describe it.
Proper adjectives take proper nouns and shift their function to fill the role of an adjective, or a word that's modifying another noun.
Proper nouns are those nouns refering to specific people, places, or things.
