sponge mushroom vs morel

sponge mushroom and morel both are nouns.

Word	Noun	Adjective	Verb	Adverb
sponge mushroom	Yes	No	No	No
morel	Yes	No	No	No

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

sponge mushroom: an edible and choice morel with a globular to elongate head with an irregular pattern of pits and ridges
morel: any of various edible mushrooms of the genus Morchella having a brownish spongelike cap

sponge mushroom (noun)	morel (noun)
an edible and choice morel with a globular to elongate head with an irregular pattern of pits and ridges	any of various edible mushrooms of the genus Morchella having a brownish spongelike cap