Sure but that's still only two levels of separation from rust, so probably good enough for a pun.

And technically iron oxide is already removed from the "true name": according to Graydon's recollection[0] it was named after the fungi[1].

[0] https://www.reddit.com/r/rust/comments/27jvdt/internet_archa...

[1] https://en.wikipedia.org/wiki/Rust_(fungus)

This is not only an English thing. In Italian rust is ruggine and those fungi in Italian are ruggine too.

How interesting. I learned of the fungus just a few days ago when I found it on a houseplant of mine. That's a fun connection.

The fungus looks a lot like pest eggs, so it was a relative relief to discover.

Sure, just thinking of the rusty brown color

Verdigris is the copper equivalent of rust.