mushroom coral vs stony coral

mushroom coral and stony coral both are nouns.

Word	Noun	Adjective	Verb	Adverb
mushroom coral	Yes	No	No	No
stony coral	Yes	No	No	No

As nouns, stony coral is a hypernym of mushroom coral; that is, stony coral is a word with a broader meaning than mushroom coral:

mushroom coral: flattened disk-shaped stony coral (usually solitary and unattached)
stony coral: corals having calcareous skeletons aggregations of which form reefs and islands

Other hypernyms of mushroom coral include madrepore, madriporian coral.

mushroom coral (noun)	stony coral (noun)
flattened disk-shaped stony coral (usually solitary and unattached)	corals having calcareous skeletons aggregations of which form reefs and islands