mycelium vs plant part

mycelium and plant part both are nouns.

Word	Noun	Adjective	Verb	Adverb
mycelium	Yes	No	No	No
plant part	Yes	No	No	No

As nouns, plant part is a hypernym of mycelium; that is, plant part is a word with a broader meaning than mycelium:

mycelium: the vegetative part of a fungus consisting of a mass of branching threadlike hyphae
plant part: any part of a plant or fungus

Other hypernyms of mycelium include plant structure.

mycelium (noun)	plant part (noun)
the vegetative part of a fungus consisting of a mass of branching threadlike hyphae	any part of a plant or fungus