Fungus

google

ref

late Middle English: from Latin, perhaps from Greek spongos (see sponge).

wiktionary

ref

Borrowed from Latin fungus(“mushroom”).

etymonline

ref

fungus (n.)

1520s, "a mushroom," from Latin fungus "a mushroom, fungus;" used in English at first as a learned alternative to mushroom (funge was used in this sense late 14c.). The Latin word is believed to be cognate with (or derived from) Greek sphongos, the Attic form of spongos "sponge" (see sponge (n.)). "Probably a loanword from a non-IE language, borrowed independently into Greek, Latin and Armenian in a form *sphong- ...." [de Vaan]